Systems and Methods for Testing a Medical Device

ABSTRACT

An ambulatory medical device comprises: a sensing component to be disposed on a patient for detecting a physiological signal of the patient; and monitoring and self-test circuitry configured for detecting a triggering event and initiating one or more self-tests based on detection of the triggering event. The ambulatory medical device senses the physiological signal of the patient substantially continuously over an extended period of time.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationNo. 62/135,910, filed Mar. 20, 2015, the disclosure of which is herebyincorporated in its entirety by reference.

BACKGROUND

1. Technical Field

The present disclosure relates to a wearable medical device and, in someaspects, to self-testing of a medical device.

2. Description of Related Art

Technology is available for correcting excessively slow heart rates(bradycardia) using implantable devices, commonly referred to aspacemakers, which deliver microjoule electrical pulses to a slowlybeating heart in order to speed the heart rate up to an acceptablelevel. Also, it is well known to deliver high energy shocks (e.g., 180to 360 joules) via external paddles applied to the chest wall in orderto correct excessively fast heart rates, and prevent the possible fataloutcome of ventricular fibrillation or certain ventricular tachycardias.Bradycardia, ventricular fibrillation, and ventricular tachycardia areall electrical malfunctions (arrhythmias) of the heart. Each can lead todeath within minutes unless corrected by the appropriate electricalstimulation.

One of the most deadly forms of heart arrythmias is ventricularfibrillation, which occurs when the normal, regular electrical impulsesare replaced by irregular and rapid impulses, causing the heart muscleto stop normal contractions and to begin to quiver. Normal blood flowceases, and organ damage or death can result in minutes if normal heartcontractions are not restored. Although frequently not noticeable to thevictim, ventricular fibrillation is often preceded by ventriculartachycardia, which is a regular but fast rhythm of the heart. Becausethe victim has no noticeable warning of the impending fibrillation,death often occurs before the necessary medical assistance can arrive.

Because time delays in applying the corrective electrical treatment canresult in death, implantable pacemakers and defibrillators havesignificantly improved the ability to treat these otherwiselife-threatening conditions. Being implanted within the patient, thedevice continuously monitors the patient's heart for treatablearrhythmias and, when such is detected, the device applies correctiveelectrical pulses directly to the heart.

Normal heart function often can be restored to a person sufferingventricular fibrillation or ventricular tachycardia by a procedure knownas cardioversion, the synchronized application of electrical therapy tothe heart muscle. Pacemakers and defibrillators that apply correctiveelectrical pulses externally to the patient's chest wall also are usedto correct such life-threatening arrhythmias, but suffer from a drawbackinsofar as it cannot be possible to apply the device in time during anacute arrhythmic emergency to save the patient's life. Such treatment isneeded within a few minutes to be effective.

Consequently, when a patient is deemed at high risk of death from sucharrhythmias, electrical devices often are implanted so as to be readilyavailable when treatment is needed. However, patients that have recentlyhad a heart attack or are awaiting such an implantable device, can bekept in a hospital where corrective electrical therapy is generallyclose at hand. Long-term hospitalization is frequently impractical dueto its high cost, or due to the need for patients to engage in normaldaily activities.

Wearable defibrillators have been developed for patients that haverecently experienced a heart attack, that are susceptible to heartarrhythmias and are at temporary risk of sudden death, and that areawaiting an implantable device. While these wearable defibrillators havebeen widely accepted and have a good reputation in the marketplace, itremains desirable to develop improvements of such devices.

SUMMARY

Non-limiting examples of the embodiments will now be described in thefollowing numbered clauses.

Clause 1: In an example, an ambulatory medical device comprises: asensing component to be disposed on a patient for detecting aphysiological signal of the patient; and monitoring and self-testcircuitry configured for detecting a triggering event and initiating oneor more self-tests based on detection of the triggering event, whereinthe ambulatory medical device senses the physiological signal of thepatient substantially continuously over an extended period of time.

Clause 2: The ambulatory medical device of clause 1, wherein thetriggering event comprises at least one of an impact and a vibrationevent experienced by the ambulatory medical device.

Clause 3: The ambulatory medical device of clauses 1 or 2, wherein theat least one of the impact and the vibration event experienced by theambulatory medical device corresponds to one of an impact level thatexceeds a predetermined impact level and a vibration level that exceedsa predetermined vibration level.

Clause 4: The ambulatory medical device of any of clauses 1-3, whereinat least one of the impact and the vibration event experienced by theambulatory medical device corresponds to an impact duration that exceedsa predetermined impact duration and a vibration duration that exceeds apredetermined vibration duration.

Clause 5: The ambulatory medical device of any of clauses 1-4, furthercomprising an electromechanical switch for detecting the at least one ofthe impact and the vibration event experienced by the ambulatory medicaldevice.

Clause 6: The ambulatory medical device of any of clauses 1-5, furthercomprising at least one of a single axis accelerometer, a multi-axisaccelerometer, and a piezoelectric transducer for detecting the at leastone of the impact and the vibration event experienced by the ambulatorymedical device.

Clause 7: The ambulatory medical device of any of clauses 1-6, whereinthe one or more self-tests comprise tests of at least one of a device,component, and subsystem of the ambulatory medical device to ensure thatthe at least one of the impact and the vibration event has not adverselyaffected the at least one of the device, component, and subsystem.

Clause 8: The ambulatory medical device of any of clauses 1-7, whereinthe triggering event comprises at least one of a software update, adevice configuration update, and a patient parameter change.

Clause 9: The ambulatory medical device of clause 8, wherein the atleast one of the software update, the device configuration update, andthe patient parameter change is initiated remotely.

Clause 10: The ambulatory medical device of clauses 8 or 9, wherein thedevice configuration update comprises an update to one or more deviceparameters set in the ambulatory medical device.

Clause 11: The ambulatory medical device of any of clauses 1-10, whereinthe triggering event is based on a user action or activity.

Clause 12: The ambulatory medical device of any of clauses 1-11, whereinthe triggering event is a wireless test signal.

Clause 13: The ambulatory medical device of clause 12, wherein thewireless test signal is initiated at a remote support center.

Clause 14: The ambulatory medical device of any of clauses 1-13, whereinthe triggering event is based on a detecting of at least one of batteryreplacement, battery removal, and battery ejection.

Clause 15: The ambulatory medical device of any of clauses 1-14, whereinthe triggering event is based on a battery level transgressing apredetermined battery charge threshold.

Clause 16: The ambulatory medical device of any of clauses 1-15, whereinthe triggering event is based on a signal indicating that one or moreelectrodes is making insufficient contact with the patient's skin.

Clause 17: The ambulatory medical device of any of clauses 1-16, whereinthe triggering event is in response to detecting moisture in excess of apredetermined moisture level.

Clause 18: The ambulatory medical device of any of clauses 1-17, whereinthe triggering event is in response to detecting strain on a devicecomponent in excess of a predetermined strain level.

Clause 19: The ambulatory medical device of any of clauses 1-18, whereinthe triggering event is in response to detecting a temperature of atleast one of the device or a component of the device greater than apredetermined maximum temperature or less than a predetermined minimumtemperature.

Clause 20: The ambulatory medical device of any of clauses 1-19, whereinthe triggering event is in response to detecting an operative connectionbetween one or more electrodes and the medical device.

Clause 21: The ambulatory medical device of any of clauses 1-20, whereinthe triggering event comprises at least one of replacement of a garmentthat comprises the ambulatory medical device worn about a torso of thepatient, replacement of a patient signal sensor, and a prompt forreplacement of at least one of the garment and the patient signal sensorin response to wear of the at least one of the garment and the patientsignal sensor over time due to use.

Clause 22: The ambulatory medical device of any of clauses 1-21, whereinthe one or more self-tests comprise one or more tests related to a typeof the triggering event.

Clause 23: The ambulatory medical device of any of clauses 1-22, whereinthe triggering event is initiated by or within a device, component, orsubsystem of the ambulatory medical device, and the one or moreself-tests comprise one or more tests of the device, component, orsubsystem of the ambulatory medical device that initiated or caused thetriggering event.

Clause 24: The ambulatory medical device of any of clauses 1-23, whereinthe monitoring and self-test circuitry is configured to classify thetriggering event and, based on the classification, determine whether toinitiate a self-test of the continuous-use medical device.

Clause 25: The ambulatory medical device of any of clauses 1-24, whereinthe monitoring and self-test circuitry is configured to store a flag ina memory of the ambulatory medical device indicating a status of thetriggering event.

Clause 26: The ambulatory medical device of any of clauses 1-25, whereinthe monitoring and self-test circuitry is always operational for themonitoring whether a primary source of power is available in theambulatory medical device.

Clause 27: The ambulatory medical device of clause 26, wherein theprimary source of power is a main battery for use with the ambulatorymedical device.

Clause 28: The ambulatory medical device of clauses 26 or 27, whereinwhen the primary source of power is not able to or is not available tosupply electrical power, a secondary source of power provides power tothe monitoring and self-test circuitry.

Clause 29: The ambulatory medical device of clause 28, wherein thesecondary source of power comprises at least one of a backup battery, acapacitor, an inductor, and a supercapacitor.

Clause 30: The ambulatory medical device of clauses 28 or 29, wherein,responsive to the triggering event when the secondary source of power isproviding power to the monitoring and self-test circuitry at least oneof: performing a subset of the one or more self-test procedures withpower from the secondary source of power, and delay performing thesubset of the one or more self-test procedures until the primary sourceof power is supplying electrical power to the monitoring and self-testcircuitry.

Clause 31: The ambulatory medical device of any one of clauses 28-30,wherein the monitoring and self-test circuitry, operating with powerfrom only the secondary source of power, is operational for monitoringduring at least one of the following: replacement of the primary sourceof power; at least one of removal of and donning of the sensingcomponent by the patient for patient showering or bathing; replacementof a garment that comprises the ambulatory medical device worn about atorso of the patient; and replacement of a patient signal sensor.

Clause 32: In another example, an ambulatory medical device comprises: asensing component to be disposed on a patient for detecting aphysiological signal of a patient; one or more components, subsystems,or systems disposed within the ambulatory medical device and operativelycoupled to the sensing component; a memory configured to store one ormore programs corresponding to one or more predetermined self-tests tobe performed on the one or more components, subsystems, or systems; andat least one processor executing a self-test component configured tocause the execution of the one or more programs stored in the memory toperform the one or more predetermined self-tests on the one or morecomponents, subsystems, or systems on a predetermined schedule; whereinthe ambulatory medical device is continuously operational during amonitoring period.

Clause 33: The ambulatory medical device of clause 32, wherein themonitoring period begins from when the sensing component is caused tobegin the detection of the physiological signal of the patient and endswhen the sensing component is caused to no longer detect thephysiological signal of the patient.

Clause 34: The ambulatory medical device of clause 32 or 33 furthercomprising at least one therapeutic element for providing a therapeuticshock to the patient.

Clause 35: The ambulatory medical device of any one of clauses 32-34,wherein the one or more predetermined self-tests comprise at least oneof the following battery tests: a battery capacity test, a batteryinternal resistance test, a battery status test, and a battery chargertest.

Clause 36: The ambulatory medical device of any one of clauses 32-35,wherein the one or more predetermined self-tests comprise a powerconverter test configured to test at least one of an output voltage anda current of a converter, a capacitor charge retention test, and acapacitor charge/discharge test.

Clause 37: The ambulatory medical device of any one of clauses 32-36,wherein the one or more predetermined self-tests comprise a test ofresponse buttons of the ambulatory medical device.

Clause 38: The ambulatory medical device of any one of clauses 32-37,wherein the one or more predetermined self-tests comprise a test of oneor more processors of the ambulatory medical device.

Clause 39: The ambulatory medical device of any one of clauses 32-38,wherein the one or more predetermined self-tests comprise a test of atleast one of the sensing component and a therapeutic element of theambulatory medical device.

Clause 40: The ambulatory medical device of any one of clauses 32-39,wherein the one or more predetermined self-tests comprise a test of atleast one of a user interface of the ambulatory medical device and acommunications module of the ambulatory medical device.

Clause 41: The ambulatory medical device of any one of clauses 32-40,wherein the self-test component is always operational for the one ormore predetermined self-tests whether or not a primary source of poweris available in the ambulatory medical device.

Clause 42: The ambulatory medical device of clause 41, wherein theprimary source of power is a main battery for use with the ambulatorymedical device.

Clause 43: The ambulatory medical device of clauses 41 or 42, whereinwhen the primary source of power is not able to or is not available tosupply electrical power, a secondary source of power provides power tothe at least one processor.

Clause 44: The ambulatory medical device of clause 43, wherein thesecondary source of power comprises at least one of a backup battery, acapacitor, an inductor, and a supercapacitor.

Clause 45: The ambulatory medical device of clauses 43 or 44, wherein,when the secondary source of power is providing power to the at leastone processor at least one of performing a subset of the one or morepredetermined self-tests with power from the secondary source of power,and delay performing the subset of the one or more predeterminedself-tests until the primary source of power is supplying electricalpower to the at least one processor.

Clause 46: In an example, an ambulatory medical device comprises: asensing component to be disposed on a patient for detecting aphysiological signal of the patient; and circuitry comprising amonitoring component for detecting a triggering event, and a self-testcomponent for executing one or more self-tests procedures on theambulatory medical device, wherein the ambulatory medical device isalways operational during a monitoring period.

Clause 47: The ambulatory medical device of clause 46, wherein themonitoring period begins from when the sensing component is caused tobegin the detection of the physiological signal of the patient and endwhen the sensing component is caused to no longer detect thephysiological signal of the patient.

Clause 48: The ambulatory medical device of clauses 46 or 47, furthercomprising a therapeutic element for delivering electrotherapy to thepatient.

Clause 49: The ambulatory medical device of any of clauses 46-48,wherein the ambulatory medical device comprises a garment worn about atorso of the patient.

Clause 50: In another example, a continuous-use medical devicecomprises: a sensing component for detecting a physiological signal of apatient; a memory; and a processor operatively connected to the sensingcomponent and the memory, the processor configured to detect at leastone of an impact and a vibration event experienced by the continuous-usemedical device; and in response to detecting the at least one of theimpact and the vibration event experienced by the continuous-use medicaldevice, store a flag in the memory of the continuous-use medical device.

Clause 51: The continuous-use medical device of clause 50, wherein theflag is configured to be retrieved from the memory when continuous useof the continuous-use medical device ends.

Clause 52: The continuous-use medical device of clauses 50 or 51,wherein the flag, when retrieved from the memory, provides an indicationthat at least one of an impact and a vibration event occurred.

Clause 53: The continuous-use medical device of clause 52, wherein theindication is displayed on at least one display device along withinformation associated with the indication to allow for review of theindication and the information by service personnel.

Clause 54: The continuous-use medical device of any of clauses 50-53,wherein the at least one of the impact and the vibration eventexperienced by the continuous-use medical device corresponds to one ofan impact level that exceeds a predetermined impact level and avibration level that exceeds a predetermined vibration level.

Clause 55: The continuous-use medical device of any of clauses 50-54,wherein at least one of the impact and the vibration event experiencedby the continuous-use medical device corresponds to an impact durationthat exceeds a predetermined impact duration and a vibration durationthat exceeds a predetermined vibration duration.

Clause 56: The continuous-use medical device of any of clauses 50-55,further comprising an electromechanical switch for detecting the atleast one of the impact and the vibration event experienced by thecontinuous-use medical device.

Clause 57: The continuous-use medical device of any of clauses 50-56,further comprising at least one of a single axis accelerometer, amulti-axis accelerometer, and a piezoelectric transducer for detectingthe at least one of the impact and the vibration event experienced bythe continuous-use medical device.

Clause 58: The continuous-use medical device of any of clauses 50-57,wherein the processor is further configured to, in response to detectingthe at least one of the impact and the vibration event experienced bythe continuous-use medical device, initiate one or more self-tests ofthe continuous-use medical device.

Clause 59: The continuous-use medical device of clause 58, wherein theone or more self-tests comprise tests of one or more devices,components, and subsystems of the continuous-use medical device toensure that the at least one of the impact and the vibration event hasnot adversely affected any of the one or more devices, components, andsubsystems.

Clause 60: In an example, an ambulatory medical device comprises: asensing component to be disposed on a patient for detecting aphysiological signal of the patient; and circuitry comprising amonitoring component for monitoring for a triggering event, and aself-test component for executing one or more self-test procedures onthe ambulatory medical device, wherein the monitoring component isalways operational for monitoring during a period beginning from whenthe physiological signal of the patient is first sensed by the sensingcomponent and ending when the monitoring is no longer needed for thepatient.

Clause 61: The ambulatory medical device of clause 60, wherein thephysiological signal can comprise a cardiac signal.

Clause 62: The ambulatory medical device of clauses 60 or 61, whereinthe device can further comprise a therapeutic element for deliveringtherapy to the patient.

Clause 63: The ambulatory medical device of any one of clauses 60-62,wherein the therapy can comprise electrotherapy

Clause 64: The ambulatory medical device of any one of clauses 60-63,wherein the continuous-use medical device can comprise a garment worn bythe patient.

Clause 65: The ambulatory medical device of any one of clauses 60-64,wherein the physiological signal of the patient can first be sensed whenthe physiological signal is either: acquired by the sensing component;received from the sensing component by a processing component that isconfigured to process the physiological signal; processed by theprocessing component for the purpose treatment analysis; or stored in amemory.

Clause 66: The ambulatory medical device of any one of clauses 60-65,wherein the monitoring is no longer needed for the patient upon theoccurrence of one or more of the following events: the patient beingimplanted with sensing and monitoring components; a changed physicalcondition of the patient whereupon the patient is medically required touse a different medical device; the patient being switched to adifferent device having more or fewer functions; the patient beingswitched to a different device used by a different caregiver; and thepatient being moved from one environment to another.

Clause 67: The ambulatory medical device of any one of clauses 60-66,wherein the monitoring component can be operational for monitoringduring at least one of the following: changing of a power source of theambulatory medical device; removal of and donning of the sensingcomponent by patient for patient showering or bathing; replacement of agarment that comprises the ambulatory medical device worn about a torsoof the patient; and replacement of a patient signal sensor.

Clause 68: The ambulatory medical device of any one of clauses 60-67,wherein replacement of the patient signal sensor can be in response towear of the patient signal sensor over a time due to use.

Clause 69: In another example, an ambulatory medical device comprises: asensing component to be disposed on a patient for detecting aphysiological signal of the patient; and circuitry configured to detecta change in a software or firmware configuration of the ambulatorymedical device, and a self-test component for, in response to the changein the software configuration, executing one or more self-testsprocedures on the ambulatory medical device.

Clause 70: The ambulatory medical device of clause 69, wherein thechange in the software configuration can comprise a software or firmwareupdate to the software of the ambulatory medical device.

Clause 71: The ambulatory medical device of clauses 69 or 70, whereinthe change in the software or firmware configuration can comprise anupdate to one or more device parameters set in the ambulatory medicaldevice.

Clause 72: In another example, an ambulatory medical device comprises: asensing component to be disposed on a patient for detecting aphysiological signal of the patient; and circuitry comprising amonitoring component for monitoring for a triggering event, and aself-test component for executing one or more self-test procedures onthe ambulatory medical device, wherein the monitoring component isalways operational for the monitoring whether or not a primary source ofpower is available in the ambulatory medical device.

Clause 73: The ambulatory medical device of clause 72, wherein theprimary source of power can be a main battery for use with theambulatory medical device.

Clause 74: The ambulatory medical device of clauses 72 or 73, wherein,when the primary source of power is not able to or is not available tosupply electrical power, a secondary source of power can provide powerto the monitoring component.

Clause 75: The ambulatory medical device of any one of clauses 72-74,wherein the secondary source of power can comprise a battery, acapacitor, a supercapacitor, an inductor, or other energy storagedevice.

Clause 76: The ambulatory medical device of any one of clauses 72-75,wherein, responsive to the triggering event when the secondary source ofpower is providing power to the monitoring component, the self-testcomponent can: (a) perform a first subset of the one or more self-testprocedures with power only from the secondary source of power; or can(b) delay performing a second subset of the one or more self-testprocedures until the primary source of power is supplying electricalpower to the monitoring component.

Clause 77: The ambulatory medical device of any one of clauses 72-76,wherein the first and second subsets of self-test procedures can be thesame or different.

Clause 78: The ambulatory medical device of any one of clauses 72-77,wherein step (a) or step (b) (of clause 76) can be performed for aperiod of time when the primary source of power is not able to or is notavailable to supply electrical power to the first component that is atleast one week or at least one month.

Clause 79: The ambulatory medical device of any one of clauses 72-78,wherein the monitoring component can be operative for directly orindirectly monitoring for the triggering event.

Clause 80: The ambulatory medical device of any one of clauses 72-79,wherein the monitoring component can indirectly monitor for theoccurrence of the event via a component, subsystem, or system that isconfigured to convert the event into a form for processing by themonitoring component.

Clause 81: The ambulatory medical device of any one of clauses 72-80,wherein the monitoring component can comprise one or moremicroprocessors, microcontrollers, or other integrated device.

Clause 82: The ambulatory medical device of any one of clauses 72-81,wherein the monitoring component, operating with power from only thesecondary source of power, can be operational for monitoring during atleast one of the following events: replacement of the primary source ofpower; removal of and donning of the sensing component by patient forpatient showering or bathing; replacement of a garment that comprisesthe ambulatory medical device worn about a torso of the patient; andreplacement of a patient signal sensor (e.g., due to wear over a periodof time).

Clause 83: In another example, an ambulatory medical device comprises: asensing component to be disposed on a patient for detecting aphysiological signal of the patient; and circuitry comprising amonitoring component for monitoring for a triggering event, and aself-test component for executing one or more self-test procedures onthe ambulatory medical device, wherein the monitoring component isalways operational for the monitoring during a period beginning fromwhen the sensing component is first configured to begin the detection ofthe physiological signal of the patient and ending when the sensingcomponent is no longer detecting the physiological signal of thepatient.

Clause 84: The ambulatory medical device of clause 83, wherein thedevice can further comprise a therapeutic element for deliveringelectrotherapy to the patient.

Clause 85: The ambulatory medical device of clauses 83 or 84, whereinthe continuous-use medical device can comprise a garment worn about atorso of the patient.

Clause 86: In another example, an ambulatory medical device comprises: amonitoring component for monitoring for one or more triggering eventsdifferent from an intended medical use of or intended medical purposefor the medical device that could potentially prevent the medical devicefrom functioning for its intended purpose; and a self-test componentresponsive to the one or more triggering events for executing one ormore self-tests procedures on the ambulatory medical device.

Clause 87: The ambulatory medical device of clause 86, wherein the oneor more triggering events can include: excessive mechanical shock;exposure to temperature greater than a predetermined maximum temperatureor less than a predetermined minimum temperature; exposure to excessivemoisture; excessive strain on a component, subsystem, or system of themedical device; exposure to a temperature change outside ofpredetermined limits; exposure to a rate of temperature change outsideof predetermined limits; prolonged vibration outside a time limit or anamplitude limit; passage of time beyond a predetermined limit; or achange in ambient pressure beyond a predetermined limit.

Clause 88: In another example, a continuous-use medical devicecomprises: one or more components, subsystems, and/or systems; a userinterface; a memory storing one or more programs for testing the one ormore components, subsystems and/or systems; and a processing elementoperatively coupled to the user interface, the one or more components,subsystem and/or systems, and the memory, the processing elementresponsive to a triggering event for executing a subset of the one ormore programs selected via the user interface.

Clause 89: The continuous-use medical device of clause 88, wherein thesubset of the one or more programs can be selected before the triggeringevent.

Clause 90: In another example, a continuous-use medical devicecomprises: one or more components, subsystems, and/or systems; an impactdetector; a memory storing one or more programs for testing the one ormore components, subsystems, and/or systems; and a processing elementoperatively coupled to the memory, the impact detector, and the one ormore components, subsystems, and/or systems, the processing elementoperative for executing the one or more programs in response todetecting via the impact detector an impact greater than a predeterminedimpact stored in the memory.

Clause 91: The continuous-use medical device of clause 90, wherein theimpact detector can comprise a piezoelectric transducer, a single axisaccelerometer, or a multi-axis accelerometer.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and characteristics of the present disclosure,as well as the methods of operation and functions of the relatedelements of structures and the combination of parts and economies ofmanufacture, will become more apparent upon consideration of thefollowing description and the appended claims with reference to theaccompanying drawings, all of which form a part of this specification,wherein like reference numerals designate corresponding parts in thevarious figures. It is to be expressly understood, however, that thedrawings are for the purpose of illustration and description only andare not intended as a definition of the limit of the invention.

Further features and other examples and advantages will become apparentfrom the following detailed description made with reference to thedrawings in which:

FIG. 1 shows an example wearable medical device;

FIG. 2 shows a front perspective view of an example monitor for awearable medical device;

FIG. 3 is an example block diagram illustrating the manner in whichfunctional components of the wearable medical device may interact;

FIGS. 4A-B illustrate example block diagrams of a wearable medicaldevice;

FIG. 5. is an example block diagram of a supervisory, e.g., watchdogtimer (WDT) scheme for a wearable medical device;

FIG. 6 is an example flow chart of a method of operation of a wearablemedical device;

FIG. 7 is an example flow chart of a self-test process;

FIG. 8 is a non-exhaustive list of example triggering events forself-tests;

FIG. 9 is a non-exhaustive list of example self-tests; and

FIG. 10 is a flow chart of an example self-test process for a batteryreplacement.

DETAILED DESCRIPTION OF THE INVENTION

As used herein, the singular form of “a”, “an”, and “the” include pluralreferents unless the context clearly dictates otherwise.

As used herein, the terms “end”, “upper”, “lower”, “right”, “left”,“vertical”, “horizontal”, “top”, “bottom”, “lateral”, “longitudinal” andderivatives thereof shall relate to the invention as it is oriented inthe drawing figures. However, it is to be understood that the inventioncan assume various alternative orientations and, accordingly, such termsare not to be considered as limiting. Also, it is to be understood thatthe invention may assume various alternative variations and stagesequences, except where expressly specified to the contrary. It is alsoto be understood that the specific devices and processes illustrated inthe attached drawings, and described in the following specification, areexamples. Hence, specific dimensions and other physical characteristicsrelated to the embodiments disclosed herein are not to be considered aslimiting.

For the purposes of this specification, unless otherwise indicated, allnumbers expressing quantities of ingredients, reaction conditions,dimensions, physical characteristics, and so forth used in thespecification and claims are to be understood as being modified in allinstances by the term “about.” Accordingly, unless indicated to thecontrary, the numerical parameters set forth in the followingspecification and attached claims are approximations that may varydepending upon the desired properties sought to be obtained by thepresent disclosure. At the very least, and not as an attempt to limitthe application of the doctrine of equivalents to the scope of theclaims, each numerical parameter should at least be construed in lightof the number of reported significant digits and by applying ordinaryrounding techniques.

Notwithstanding that the numerical ranges and parameters setting forththe broad scope of the invention are approximations, the numericalvalues set forth in the specific examples are reported as precisely aspossible. Any numerical value, however, inherently contain certainerrors necessarily resulting from the standard deviation found in theirrespective testing measurements.

Also, it should be understood that any numerical range recited herein isintended to include all sub-ranges subsumed therein. For example, arange of “1 to 10” is intended to include any and all sub-ranges betweenand including the recited minimum value of 1 and the recited maximumvalue of 10, that is, all subranges beginning with a minimum value equalto or greater than 1 and ending with a maximum value equal to or lessthan 10, and all subranges in between, e.g., 1 to 6.3, or 5.5 to 10, or2.7 to 6.1.

As used herein, the terms “communication” and “communicate” refer to thereceipt or transfer of one or more signals, messages, commands, or othertype of data. For one unit or component to be in communication withanother unit or component means that the one unit or component is ableto directly or indirectly receive data from and/or transmit data to theother unit or component. This may refer to a direct or indirectconnection that may be wired and/or wireless in nature. Additionally,two units or components may be in communication with each other eventhough the data transmitted may be modified, processed, routed, and thelike, between the first and second unit or component. For example, afirst unit may be in communication with a second unit even though thefirst unit passively receives data, and does not actively transmit datato the second unit. As another example, a first unit may be incommunication with a second unit if an intermediary unit processes datafrom one unit and transmits processed data to the second unit. It willbe appreciated that numerous other arrangements are possible.

This disclosure relates to tests performed in and/or on medical devices.For example, tests as disclosed herein can be performed in and/or on amedical devices that are configured to be substantially always on or forcontinuous use (after initially being powered-on) for a predeterminedmedical purpose. For example, such medical devices can includemonitoring devices configured to continuously monitor a patient forcertain medical conditions for extended periods of time, for example,for over 4 hours (e.g. treatment and monitoring devices such as sleepapnea devices), over 12 hours (e.g. treatment and/or monitoring devicessuch as mobile cardiac monitoring devices, wearable defibrillatordevices, etc.), and including for substantially continuous monitoringover time periods over 24 hours or even several days. Such devices maymonitor the patient substantially continuously, aside from periodsduring which the patient may periodically remove the device, such as forshowering, refitting, changing a component of the device, etc. In someimplementations, such devices are capable of, in additional tomonitoring for medical conditions, providing treatment to a patientbased on detecting a predetermined medical condition. For example,medical devices as disclosed herein can include automated always- orcontinuously-on (or continuous-use) defibrillators, such as in-facilitydefibrillators (e.g., for patients that are confined to a limited spacewithin a facility, such as, within a hospital environment, to apatient's room) or outpatient wearable defibrillators. Such devices canbe configured to monitor a patient for an arrhythmia condition such asventricular tachycardia (VT) or ventricular fibrillation (VF). If thearrhythmia condition is detected, the device can automatically provide adefibrillation pulse or shock to treat the condition.

Other example devices capable of performing or running the tests andtechniques discussed herein include automated always- or continuously-onportable defibrillators for use in certain specialized conditions and/orenvironments such as in combat zones or within emergency vehicles. Suchdevices may need to remain always powered ON so that they may be usedimmediately (or substantially immediately) in a life-saving emergency.In some examples, the automated extended-use defibrillators describedherein can be pacing-enabled, e.g., capable of providing therapeuticpacing pulses to the patient.

For example, a continuous-use medical device as described herein caninclude at least one component, subsystem, or system (e.g., powered orunpowered circuitry or one or more processors) that is substantiallyalways enabled during a predefined period or in a state that isavailable for immediate (or substantially immediate) use for at leastone of the device's primary uses as discussed in further detail below.For example, in the case of certain treatment and monitoring devicessuch as sleep apnea devices the predefined period over which the devicesmay substantially continuously monitor for certain sleep apnea-relatedconditions may be over 4 hours. In the case of certain other treatmentand/or monitoring devices such as mobile cardiac monitoring devices,ambulatory and/or wearable defibrillator devices, such predefined periodmay be over 12 hours. These devices can be configured for substantiallycontinuous monitoring over time periods over 24 hours or even severaldays. As noted, such devices may monitor the patient substantiallycontinuously, aside from periods during which the patient mayperiodically remove the device, such as for showering, refitting,changing a component of the device, etc.

For example, medical devices that can implement one or more of thefeatures described herein can be invasive (e.g., an implantabledefibrillator and/or pacing device) or non-invasive (e.g., a wearabledefibrillator). For example, the medical device may be ambulatory, e.g.,the device is capable of and designed for moving with the patient.

Example Medical Device

In an example and with reference to FIG. 1, the medical device can beconfigured as a wearable defibrillator, denoted generally as referencenumeral 1, such as the LifeVest® wearable defibrillator available fromZOLL® Medical Corporation of Pittsburgh, Pa. and Chelmsford, Mass. Thewearable defibrillator 1 can be worn by a patient and can include agarment, generally denoted as reference numeral 2, an electrodeassembly, denoted generally as reference numeral 3, and a monitor,denoted generally as reference numeral 5, operatively connected to theelectrode assembly 3. The garment 2 can be configured as a harness,shirt, or other apparel and is configured to permit the patient to wearthe defibrillator 1. The electrode assembly 3 can be configured to beassembled within the garment 2.

Such wearable defibrillators can be typically worn nearly continuouslyfor two to three months at a time. During the period of time in whichthey are worn by the patient, the wearable defibrillator 1 can beconfigured to continuously monitor the vital signs of the patient, to beuser-friendly and accessible, to be as light-weight, comfortable, andportable as possible, and to be capable of delivering one or morelife-saving therapeutic shocks when needed. Non-limiting examples ofsuitable wearable defibrillators are disclosed in U.S. Pat. Nos.4,928,690; 5,078,134; 5,741,306; 5,944,669; 6,065,154; 6,253,099;6,280,461; 6,681,003; 8,271,082; and 8,369,944, the entirety of all ofwhich are incorporated by reference herein.

With continued reference to FIG. 1, the electrode assembly 3 includes aplurality of electrodes, such as electrodes 7 a, 7 b, 7 c, and 7 d,which contact a patient 9 when the wearable defibrillator 1 is worn bythe patient 9. According to one example, the electrodes 7 a, 7 b, 7 c,and 7 d are configured to receive ECG signals from the patient 9. Forinstance, the electrodes 7 a, 7 b, 7 c, and 7 d can be positioned on thepatient 9 to receive ECG signals from a front-to-back channel and from aside-to-side channel. For example, the front-to-back (FB) channel caninclude one of electrodes 7 a, 7 b, 7 c, and 7 d positioned on the chestof the patient 9 and another one of the electrodes 7 a, 7 b, 7 c, and 7d positioned on the back of the patient 9. For example, the side-to-side(SS) channel includes one of the electrodes 7 a, 7 b, 7 c, and 7 dpositioned on the left side of the chest and another one of theelectrodes 7 a, 7 b, 7 c, and 7 d positioned on the right side of thechest of the patient 9. In some examples, the electrodes 7 a, 7 b, 7 c,and 7 d can be operatively connected to a distribution node 11 of theelectrode assembly 3.

In some implementations, the electrode assembly 3 can also comprisetherapy pads 13 a, 13 b, and 13 c operatively connected to thedistribution node 11. The therapy pads 13 a, 13 b, and 13 c can beconfigured to deliver one or more life-saving therapeutic shocks whenneeded. In some examples, the electrode assembly 3 can also includeother sensing electrodes and devices (not shown) such as, but notlimited to, heart beat sensors, accelerometers, and sensors capable ofmeasuring blood pressure, heart rate, thoracic impedance, respirationrate, heart sounds, acoustic sensors, audio transducers, and theactivity level of the subject. The electrode assembly 3 can furthercomprise a tactile stimulator 12, such as a vibrator, positioned withinthe distribution node 11 to provide tactile stimulation to the patient 9as described in greater detail hereinafter.

The monitor 5 can be operatively connected to one or more of the therapypads 13 a, 13 b, and 13 c and electrodes 7 a, 7 b, 7 c, and 7 d via,e.g., a trunk cable 15 or any other suitable cable or connection device.Wiring or other connection devices can be used to connect at least oneportion of the distribution node 11 to the electrodes 7 a, 7 b, 7 c, and7 d and therapy pads 13 a, 13 b, and 13 c. Alternatively, the monitor 5can be operatively connected to one or more of the electrodes 7 a, 7 b,7 c, and 7 d, therapy pads 13 a, 13 b, and 13 c, and distribution node11 by a wireless connection or a combination of wireless and wiredconnections.

The distribution node 11 is configured to obtain ECG data from theelectrodes 7 a, 7 b, 7 c, and 7 d, digitize this data, and transfer thisdata to the monitor 5. Accordingly, the distribution node 11 includes aprocessor, such as a belt node processor (BNP) 17 (see FIGS. 3, 4A, and4B), operatively connected to electrodes 7 a, 7 b, 7 c, and 7 d andconfigured to receive signals representing the ECG of the patient 9 fromthe electrodes 7 a, 7 b, 7 c, and 7 d. The BNP 17 communicates with themonitor 5 via a Controller Area Network (CAN) bus 19 (see FIGS. 3 and 4)or any other suitable bus that comprises trunk cable 15. The BNP 17 isalso configured to sense whether one or more of electrodes 7 a, 7 b, 7c, and 7 d have fallen off the patient's body, to control the tactilestimulator 12, and to fire the electrode gel interface for providingelectrolytic gel to the therapy pads 13 a, 13 b, and 13 c when a requestis received from the monitor 5.

With reference to FIG. 2 and with continuing reference to FIG. 1, themonitor 5 can include an external housing 31 having a port to which theECG electrodes 7 a, 7 b, 7 c, and 7 d and therapy pads 13 a, 13 b, and13 c of the electrode assembly 3 are operatively coupled to the monitor5 via the trunk cable 15. The monitor can include one or more batteries,such as a rechargeable and removable battery (not shown) positionedwithin a battery housing. The battery has sufficient capacity to allowthe wearable defibrillator 1 to administer one or more therapeuticshocks as well as provide power to all of the internal components of thedefibrillator 1. The external housing 31 further comprises at least one,and for example, a pair of patient response buttons 41 positioned, forexample, in the top left corner of the housing 31. The external housing31 of the defibrillator can also include a display screen 43 forproviding information to the patient 9 and for providing a user inputdevice to the patient 9. Further details of the monitor 5 can be foundin U.S. patent application Ser. No. 14/448,997, which is herebyincorporated by reference in its entirety.

System Architecture of an Example Medical Device

With reference to FIG. 3 and with continuing reference to FIGS. 1 and 2,the functional components of the monitor 5 can be provided within theexternal housing 31 of the monitor 5. In one example, the functionalcomponents can be provided on a distributed printed circuit board asdisclosed in U.S. patent application Ser. No. 14/448,857, which ishereby incorporated by reference in its entirety. In one example, thefunctional components can comprise a discharge module 42, an energystorage module 44, a controller module 47, and a communication module49. The discharge module 42 is for selectively delivering an energypulse to the patient 9 via therapy pads 13 a, 13 b, and 13 c. The energystorage module 44 can be operatively connected to the discharge module42. The controller module 47 can be operatively connected to the energystorage module 44 and can be configured to control the delivery of theenergy pulse to the patient 9. The communication module 49 can beoperatively connected to the controller module 47.

In one example, the energy storage module 44 can include a high voltagepower convertor 64 (shown in FIG. 4) and a capacitive device, such as abank of capacitors 67 (shown in FIG. 4). The discharge module 42 caninclude at least one high-voltage switch (not shown) and can beconfigured to selectively deliver an energy pulse stored in the energystorage module 44 to the patient 9 based on a signal from the controllermodule 47. The energy pulse is sent from the discharge module 42 throughthe port 38 to the patient 9 via therapy pads 13 a, 13 b, and 13 c.

A biphasic waveform is delivered to the patient 9 by switching the atleast one high voltage switch of the discharge module 42. The operationof the pulse delivery system can be dynamic and depend on the patient'sbody impedance while the pulse is being delivered. For example, anamount of energy delivered can be held constant while varying theduration of the first phase and the second phase. In another example, amonophasic waveform can be delivered to the patient depending on thepatient's condition.

With reference to FIGS. 4A-4B, and with continuing reference to FIGS.1-3, controller module 47 can include one or more processors 69, 71(FIG. 4A) each of which operates under the control of a control programthat executes at runtime for performing certain functionalities of thewearable defibrillator 1. In one example, controller module 47 caninclude at least a first processor 69 and a second processor 71. In oneexample, the first processor 69 and the second processor 71 can beconfigured to function as disclosed in U.S. Pat. No. 8,904,214, which ishereby incorporated by reference in its entirety.

In some implementations, one of the first and second processors 69, 71may be a multi-core processor. The interface between the processors 69,71 can be implemented as a serial interface. For example, the firstprocessor 69 can be configured to include an operating system (e.g.,accessible via a shell) and include one or more programs for controllingthe overall continuous-use device, including its various components,subsystems, and systems. For example, in a continuous-use defibrillator,the second processor 71 can be configured to manage and operate the highvoltage circuitry used to deliver, monitor, and modify one or moredefibrillation pulses to the patient. In this regard, for example, thesecond processor 71 can be configured to run as a slave to the firstprocessor 69. As such, a monitoring component and a self-test componentas described herein can be executed within the first processor 69 andmake use of shell features to interact with various other devicecomponents, subsystems, and systems.

Also, or alternatively to processors 69, 71, controller module 47 (FIG.4B) can include discrete and/or integrated electrical and/or electroniccircuitry 75 that is configured to perform the functions describedherein (either alone or in combination with one or more of processors69, 71), but not under the control of a control program. In an example,the electrical and/or electronic circuitry 75 of controller module 47can include one or more discrete elements, such as, without limitation,one or more of the following discrete elements: transistor, resistor,capacitor, inductor, memristor, diode, loudspeaker, buzzer, linearvariable differential transformer (LVDT), rotary encoder, shaft encoder,inclinometer, motion sensor, vibration sensor, flow meter, strain gauge,accelerometer, thermocouple, thermopile, thermistor, resistancetemperature detector (RTD), bolometer, thermal cutoff, magnetometer,gauss meter, hygrometer, photo resistor, LED or other light emittingdevice, and/or antenna.

In an example, the electrical and/or electronic circuitry 75 ofcontroller module 47 can also or alternatively include one or moreintegrated circuits, such as, without limitation, analog integratedcircuit, digital integrated circuit, mixed signal (analog and digital)integrated circuit, application specific integrated circuit (ASIC),programmable logic device (PLD), gate array, field programmable gatearray (FPGA), and/or microelectromechanical systems (MEMS). In anexample, these one or more integrated circuits can include one or moreof analog-to-digital converter (ADC), a multiplexer, a power regulator,or some combination thereof.

In another example, controller module 47 is operatively connected to auser interface 70 (comprised of one or more response buttons 41 and/ordisplay screen 43), the high voltage power convertor 64, and thedischarge module 42. Such a configuration allows at least one of thefirst processor 69 and the second processor 71 to be capable ofproviding output to a patient 9, for example through the display screen43, and accept input from the patient 9, for example from responsebuttons 41, as well as provide instructions to the high voltage powerconverter 64 and/or the discharge module 42 to deliver a therapeuticshock to the patient 9. For example, the first processor 69 and thesecond processor 71 shown in FIG. 4A or circuitry 75 shown in FIG. 4Bcan be used to provide certain functionality within the wearabledefibrillator 1 such as, but not limited to: high voltage convertercontrol; discharge module control; real time clock (date/time) for thesystem; execution of timing-critical software or functions such astherapy pulse synchronization (e.g., synchronizing the pulse delivery toavoid delivering a pulse on a T wave); ECG acquisition from the CAN bus19; ECG monitoring and arrhythmia detection; user interface control;treatment sequencing; audio message generation; and data communicationsand storage. An example of the methods used to detect abnormal heartrhythms can be found in U.S. Pat. No. 5,944,669, which is assigned tothe assignee of the present application and which is hereby incorporatedby reference in its entirety. These functionalities can be performed bycircuitry 75 distributed between the two processors 69 and 71, or somecombination of circuitry 75 and one or more of processors 69 and 71. Forexample, the first processor 69 can perform certain ones of thesefunctionalities while others of the functionalities can be performed bythe second processor 71.

In some implementations, the BNP 17 can be operatively connected to thecontroller module 47. The BNP 17 can act as an ECG data acquisitionengine for the controller module 47 via the CAN bus 19 as describedhereinabove.

In one example, the communication module 49 can be controlled by atleast one of the processors 69, 71 or circuitry 75 of the controllermodule 47 and can provide various devices for communicating informationto and from the monitor 5. For instance, the communication module 49 caninclude a GPS transceiver, a Bluetooth transceiver, a Wi-Fi modem, and acellular modem. The communication module 49 is configured to communicatewith a remote server provided via the cellular modem. Alternatively, ifcellular communication capabilities are not available, the communicationmodule 49 can communicate with the remote server via the Wi-Fi modem.

For the purpose of simplicity, hereinafter the invention will bedescribed with reference to monitor 5 shown in FIG. 4A that includescontroller module 47 having processors 69, 71. However, this is not tobe construed as limiting the invention since it is envisioned thatcontroller module 47 can, also or alternatively to processors 69, 71,include circuitry 75.

With reference to FIG. 5 and with continuing reference to FIGS. 4A and4B, in one example, the controller module 47 can include circuitry orcircuit 76, e.g., implemented on a programmable logic device (PLD), toprovide, among other things, a supervisory circuit function. The circuit76 can be configured to provide interfacing support and input/outputtranslations between the first processor 69, the second processor 71,and various system peripherals 77. The circuit 76 can be configured toimplement a processor supervisory function. For example, such asupervisory function can be a watchdog timer (WDT) function 75 a, 75 b.In general, the supervisory function can monitor one or all three of thefirst processor 69, the second processor 71, and the BNP 17. In oneexample, the first processor 69 and the second processor 71 can berequired to periodically service the WDT 75 a, 75 b function to preventa timeout from occurring.

Operation of the Example Medical Device

With reference to FIG. 6, a description of the manner in which themonitor 5 operates when an abnormal event is detected by the detectionalgorithm of one or both of the processors 69, 71 will be described.Initially, at least one of the processors 69, 71 is running thedetection algorithm and detecting normal sinus rhythm at 100. In oneexample, one of the processors 69, 71 can be running the detectionalgorithm and the other of the processors 69, 71 can be in a low-powersleep state. When the detection algorithm detects a VT or VF rhythmtype, it dispatches an event to the state machine that is run on atleast one of the processors 69, 71. The state machine exits the NormalSinus Rhythm Monitoring state 100 when the event is received andtransitions to a notification state 102 that begins the patientnotification sequence to provide stimuli to the patient to make thepatient aware that an event has been detected and starts a capacitorcharge cycle. After the capacitors are fully charged a Charge CycleComplete event 104 can be sent to at least one of the processors 69, 71.As shown in FIG. 6, a timer can be used to determine when to release thegel (see 106) and allow timing of a gel wetting period (see 105) toreduce transthoracic impedance.

At any point after the notification state 102, the patient can cancelthe treatment sequence by pressing the response buttons 41 and thesystem acknowledges the patient response and stops charging capacitors110. This is shown by arrows 112, 115, and 116. If the patient does notrespond to the alarms and the timer for gel wetting expires, the statemachine issues a command 120 to at least one of the processors 69, 71 tofire the defibrillator and treat the patient. Since at least one of theprocessors 69, 71 is continuously monitoring the patient's rhythm, theat least one processor 69, 71 can detect a sinus rhythm if thedefibrillation was successful and send an event notification to thestate machine.

An automated continuous-use medical device as described herein, such aswearable defibrillator 1, can be used for monitoring and, optionally,treating a patient. For example, the automated continuous-use medicaldevice can be designed to be always-on and configured to perform one ormore self-tests, including, without limitation, one or more event-drivenself-tests, one or more periodic self-tests, one or more aperiodicself-tests, or some combination thereof. Non-limiting examples of suchself-tests will now be described with reference to a continuous-usedefibrillator that is used for monitoring an ambulatory patient anddelivering a shock when necessary. However, the disclosure herein ofwearable defibrillator 1 is not to be construed as limiting thedisclosure in any manner as it is envisioned that the present inventioncan also be utilized with any medical device that is designed to bealways on for monitoring and, optionally, treating a patient.

In general, in a continuous-use medical device that is used formonitoring an ambulatory patient and delivering a shock when necessary,one or more circuits or processors (e.g., under the control of programsstored in a memory accessible to the one or more processors) of themedical device can perform one or more of the self-tests describedherein based on a triggering event such as, but not limited to, one ormore triggering events.

In an example, the continuous-use medical device can include one or moremonitoring elements or components, e.g., circuitry or processors, whichare always operational and monitoring for triggering events throughoutan expected period of use of the device by a patient as described infurther detail below. For example, in certain implementations, one ormore monitoring components can be always operational throughout a lifespan of the continuous-use device.

In some implementations, one or more monitoring elements can includenon-powered elements, e.g., elements that do not require external powerto operate. For example, such an element can include a mechanical switchthat can detect an impact on the device or other device abuse, andchange its state from ON to OFF (or vice-versa). Such a change in statecan cause a self-test to be executed by the continuous-use medicaldevice. Alternatively, as detailed below, a low power microprocessor canbe configured to be always operational in a monitoring state regardlessof the primary power status of the medical device.

In implementations, the continuous-use medical device can include one ormore self-testing components that can execute one or more self-testsbased on the triggering events. For example, such self-testingcomponents can include circuitry and/or processors that may be alwaysoperational throughout an expected period of use of the device asdescribed below. In some examples, one or more of the monitoring andself-testing components can be included in the monitor 5 (see, e.g.,FIG. 1) of a wearable defibrillator. Further, it should be apparent to aperson skilled in the art that aspects of the monitoring elements andthe self-testing components can be together included in a single circuitor microprocessor or distributed over multiple circuits ormicroprocessors.

One or more examples described below in connection with triggeringevents for self-tests and self-tests performed by the medical device arewith specific reference to a microprocessor as an example of circuitrythat can perform in the manner discussed in the example. However, thisis not to be construed as limiting the invention since it is envisionedthat the microprocessor mentioned in any such example can be replacedwith any suitable and/or desirable circuit or circuitry that can performthe operation(s) disclosed in the example.

Certain example triggering events are described below in the context ofan example continuous-use defibrillator. It should be understood thatthese examples are equally applicable to other continuous-use medicaldevices, including continuous-use cardiac monitoring devices, ortherapeutic devices, e.g., devices configured for therapeutic electricalcurrent delivery such as pacing, and/or TENS (transcutaneous electricalnerve stimulation).

In an example, the circuitry 75 of the controller module 47 of thecontinuous-use medical device is configured to detect a triggering eventas described in further detail below. As discussed hereinabove, thetriggering event may be any number of events detected by any number ofsensors associated with the continuous-use medical device. For example,the triggering event may be the detection of an impact above apredetermined threshold on the continuous-use medical device by animpact detector, such as a piezoelectric transducer, a mechanicalswitch, a single axis accelerometer, or a multi-axis accelerometer. Thisimpact may be due to the continuous-use medical device being dropped bythe patient, for example. In another example, the triggering event maybe a detection of the sensing electrodes being removed from contact withthe patient or detection of a temperature in excess of the exposure totemperature greater than a predetermined maximum temperature or lessthan a predetermined minimum temperature by a temperature sensorassociated with the continuous-use medical device. In yet anotherexample, the triggering event may be any one or more of the triggeringevents listed in FIG. 8.

In one example, the continuous-use medical device may be configured todetect one or more of the triggering events and set a flag in the memoryof the continuous-use medical device that the one or more triggeringevent occurred. Depending on predefined rules in a program stored in amemory of the continuous-use device, the device may or may not initiatea self-test in response to the triggering event. This flag can beconfigured to be retrieved by service personnel, for example, whencontinuous-use of the medical device is deemed to have ended. Theseflags are configured to provide an indication to the service personnelof particular events that occurred during patient use of thecontinuous-use medical device and allow the service personnel toproperly diagnosis any problems with the continuous-use medical device.The indication provided by the flags may be displayed on the display ofthe continuous-use medical device or on an external display deviceoperatively connected to the continuous-use medical device when thedevice is being serviced.

The circuitry 75 can be configured to store a flag in the memory (e.g.,memory available to processors 1 and 2 (FIG. 5) of the continuous-usemedical device. The flag can be in the form of a Yes/No (or ON/OFF) dataelement configured to indicate whether an underlying triggering eventhas occurred, e.g., based on one or more data conditions or thresholdscorresponding to the parameter being monitored. For example, if the flagis set to “Yes” or “ON” an indication may be provided that a particulartriggering event has occurred. On the other hand, if the flag is set to“No” or “OFF”, the element indicates that conditions for a giventriggering event were not met. Using the detection of an impact exampleprovided above, the impact detector sends a signal to the circuitry 75of the controller module 47 that the continuous-use medical device hasexperienced an impact or vibration event. The circuitry 75 of thecontroller module 47 analyzes the signal from one or more impact orvibration detector disposed in the device as described below anddetermines whether the detected impact is above a predeterminedthreshold. If the impact or vibration transgresses a predeterminedthreshold or has a duration that transgresses a predetermined durationlevel, the circuitry 75 is configured to store a flag in the memory ofthe continuous-use medical device. In an implementation, different flagsmay be used to record transgression of thresholds corresponding to animpact or a vibration. For example, a first flag may be used to recordan event involving the transgression of a predetermined impact orvibration threshold level, and a second flag may be used to record anevent involving transgression of a predetermined impact or vibrationduration level. Similarly, separate flags may be maintainedcorresponding to each of the impact detection and the vibrationdetection events.

The flag may be configured to be retrieved and/or read from the memoryof the continuous-use device when such continuous-use has ended. In oneexample, the use of the medical device may be deemed to be at an endwhen the device is sent back to the manufacturer to be serviced. In thiscontext, the flag when retrieved from the memory, can provide anindication that the at least one triggering event, such as, but notlimited to, the detection of an impact, change in temperature, orelectrode fall-off, occurred. The indication may be displayed on adisplay device configured to allow service personnel to review suchindications. This allows service personnel to have the opportunity toreview various events that occurred with the device when it was incontinuous use so that they can accurately and efficiently diagnosis anyproblems with the device before returning the device to the patient or anew patient. The display device may be the display 43 of thecontinuous-use medical device or it may be a display external from thecontinuous-use medical device and operatively connected thereto. Thedisplay may provide a coding associated with the flags (e.g., anumerical, alphanumeric, color, shade, pattern, or other coding) toindicate priority, criticality, or other classification of an underlyingflag. For example, such classifications may be predefined through one ormore rules associated with a program stored in a memory of thecontinuous-use medical device or the display device employed by theservice personnel to review the flag information. For example, an impactevent flag may be coded red to indicate a higher criticality than, forexample, an electrode fall-off event.

In another example, the circuitry 75 of the controller module 47 may beconfigured to classify the triggering event prior to storing the flag inthe memory in response to the at least one triggering event and, basedon the classification, determine whether to store the flag in the memoryor initiate a self-test of the continuous-use medical device. Morespecifically, some triggering events may be considered minor events thatmost likely will not require a complete self-test of the continuous-usemedical device. In such instances, rather than running a self-test onthe device, the circuitry 75 will merely set a flag in memory that thetriggering event occurred for later review by service personnel. Suchtriggering events include, but are not limited to, detection of animpact on the at least one medical device, detection of an electrodebeing removed from contact with the patient, and detection of atemperature in excess of the exposure to temperature greater than apredetermined maximum temperature or less than a predetermined minimumtemperature.

However, certain triggering events may adversely affect the manner inwhich the continuous-use medical device operates. Accordingly, thecircuitry 75 of the controller module 47 may be configured to initiate aself-test if such a triggering event is detected. Such triggering eventsinclude, but are not limited to, detection of replacement of a batteryof the continuous-use medical device, completion of a reset of thecontinuous-use medical device, and detection of delivery of at least oneshock to the patient.

TRIGGERING EVENTS FOR SELF-TESTS Initialization and Baselining

In one example, circuitry (e.g., including a microprocessor) in thecontinuous-use defibrillator can run one or more self-tests as part ofan initialization process of the continuous-use defibrillator, whichinitialization process may occur, for example, after a software or userinitiated reset of the continuous-use defibrillator.

The tests described herein may be performed in a manner and at timesthat do not interfere with a substantial use of the device. For example,if the device is actively performing an important task, such as chargingthe device capacitors, the device may suspend a scheduled test or even areset (depending on the reset conditions) until after the task iscompleted (or complete cancel the test or reset).

For example, the tests can be run before or after a baselining process,e.g., a process of recording a baseline template of a patient'smonitored parameters, is performed. An example baseline process isdescribed in U.S. Pat. No. 5,944,669, which disclosure is incorporatedherein in its entirely. For example, a baselining process can beinitiated periodically or aperiodically in response to predeterminedevents, and as such, tests associated with the baseline process canfollow a similar schedule.

In some examples, one or more self-tests may be based on the type of thetriggering event as described in further detail below. For example, atriggering event initiated by or within a device, component, or asubsystem of the medical device may be the basis for initiating aself-test of the device, component, or subsystem. In some cases, one ormore of such self-tests may also include diagnostic tests of the otherdevices, components, or subsystems related to the device, component, orsubsystem associated with the triggering event. For example, thetriggering event can be a battery event, such as battery replacement,removal, or ejection, as described below. A battery related triggeringevent may also be based on the battery charge level transgressed apredetermined battery level threshold. Such battery-related triggeringevents can cause one or more battery related self-tests to be initiated.For example, such tests can include tests of the battery voltage, highvoltage converter coupled to the battery, battery power consumptiontests, battery gas gauge drain tests, and tests of the internalresistance of the battery. These battery related tests can also includetests of components, devices, and/or subsystems that are directed orindirectly coupled to the battery.

In some implementations, a triggering event may be an indication that anelectrode has fallen off or is causing a noisy ECG signal. Accordingly,one or more self-tests related to the ECG event can include tests of theECG sensor circuit, sensor impedance checks, and/or electrode integrityverification tests.

Download of Patient Profile

Examples of initialization processes that could trigger a self-testcomprise, without limitation, completion of the download of all or partof a patient profile or all or part of an updated patient profile intothe memory of the continuous-use defibrillator accessible to themicroprocessor of the continuous-use defibrillator. The patient profileor updated patient profile can comprise data unique to a patient that isto wear the defibrillator during use. This patient profile (or portionthereof) may comprise, for example, without limitation, baseline ECGsignals or other criteria, such as threshold heart rate values that themicroprocessor of the defibrillator utilizes to determine whether or notthe patient is experiencing an arrhythmia event and, if so, to deliver ashock.

Button(s) Actuation

In another example, the microprocessor of the continuous-usedefibrillator runs a self-test in response to actuation of one or morebuttons (e.g., response buttons 41 of monitor 5) of the defibrillatorwhile in use or as part of the initialization process (described above).

Periodically, aperiodically, or in response to a triggering event, thecontinuous-use device may carry out a test of the response buttons asfollows. For example, the test may involve determining whether theactuation of the response buttons is being detected by the responsebutton circuitry. For example, a test of the response buttons caninclude determining whether the one or more processors of the device isreceiving an actuation signal associated with actuation of the responsebuttons.

Detection of Mechanical Impact or Vibration

In another example, in response to the microprocessor of thecontinuous-use defibrillator determining via an accelerometer or otherimpact or vibration detecting device, such as, without limitation, apiezoelectric device, of the continuous-use defibrillator that thecontinuous-use defibrillator has experienced one or more impacts orvibration in excess of a predetermined impact (amplitude) or vibrationlevel, or a predetermined time limit stored in a memory accessible bythe microprocessor, the microprocessor can set a flag and/or initiateself-testing of the continuous-use defibrillator. In another example,another impact detecting device can be an electromechanical or amechanical switch that configured to change state, e.g., from an openstate or closed state, or vise verse, in response experiencing a g-forcein excess of a g-force the electromechanical or mechanical switch isdesigned to experience without changing state. In this manner, thedevice can be configured to determine if any device, component, orsubsystem of the medical device has been adversely affected by theimpact or the vibration. For example, the microprocessor can beprogrammed to be responsive to this electromechanical or mechanicalswitch changing state to initiate self-testing of the continuous-usedefibrillator. An example of a continuous-use defibrillator that iscapable of detecting impact is disclosed in U.S. patent application Ser.Nos. 14/180,775 and 14/175,433 and U.S. Pat. No. 8,676,313, each ofwhich is hereby incorporated by reference in its entirety. Thecontinuous-use defibrillator can also include a GPS which can be used bythe microprocessor to record a GPS location where the continuous-usedefibrillator experienced the impact in excess of the predeterminedimpact level. Examples of precision microsensors for use aselectromechanical or mechanical switches for applications describedherein are the SQ-SEN, ASx, and the MIN product families fromSignalQuest, Inc. of Lebanon, N.H.

Remotely Initiated Self-Test(s)

In another example, where the continuous-use defibrillator compriseswireless communication capabilities, such as, without limitation,cellular telephone circuitry, Wi-Fi circuitry, and/or another suitableand/or desirable wireless communication circuitry as discussedhereinabove, one or more self-tests can be triggered via the wirelesscommunication capability. For example, via the wireless communicationcapability of the continuous-use defibrillator, the continuous-usedefibrillator can receive a wireless test signal which causes themicroprocessor to initiate self-testing of the continuous-usedefibrillator. In another example, if the wireless capability isutilized to update software or firmware of the continuous-usedefibrillator, including patient profile information, the microprocessorcan initiate self-testing in response to the completion of such softwareor firmware update. In another example, if the wireless capability canbe utilized by the patient to wirelessly contact a remote support centerwith an inquiry or notification of an issue, the microprocessor caninitiate self-testing of the continuous-use defibrillator in response tosuch patient initiated inquiry or notification, or in response toreceiving a wireless communication (in some implementations, notnecessarily a test signal) from the remote support center. In anotherexample, the microprocessor of the continuous-use defibrillator can beprogrammed to periodically or occasionally wirelessly transmit theresults of self-tests to the remote service center for analysis orstorage. If the remote service center determines that one or more of theself-tests, either standing alone or in comparison to other self-teststhat have been reported, indicate the potential for an issue with acomponent, subsystem, or system of the continuous-use defibrillator, thecustomer service center can wirelessly contact the microprocessor viathe wireless capabilities of the continuous-use defibrillator to causethe microprocessor to initiate one or more self-tests and to wirelesslyreport the results of said one or more self-tests back to the servicecenter via the wireless capabilities of the defibrillator. In anotherexample, the service center can wirelessly request the microprocessor toperform one or more self-tests via the wireless capabilities of thedefibrillator for any reason, e.g., as part of a periodic or occasionalassessment of the operational capabilities of the defibrillator, whennotifying a patient of a potential operational issue in thecontinuous-use defibrillator, and/or when updating the patient profilestored in a memory of the defibrillator. It should be understood to aperson skilled in the art that other reasons could be contemplated andshould not be limited to the ones enumerated herein.

In another example, one or more self-tests can be downloaded into thecontinuous-use defibrillator on or about the time it is desired toperform said one or more self-tests. In this example, it is envisionedthat said one or more self-tests can be downloaded from an externaldevice wirelessly into a memory of the continuous-use defibrillatorunder the control of the microprocessor of the continuous-usedefibrillator without the need for patient interaction to cause saiddownload. Also or alternatively, the user of the continuous-usedefibrillator can initiate a request for one or more self-tests to bewirelessly downloaded into the continuous-use defibrillator, e.g., bypressing one or more buttons (real or virtual) on monitor 5.

Execution-Time Download Self-Test(s)

In an example, one or all of the self-tests to be run by the externaldefibrillator can be wirelessly downloaded into a memory of thecontinuous-use defibrillator accessible to the microprocessor of thecontinuous-use defibrillator on or about the time it is desired for saidone or more self-tests to be executed. Also or alternatively, a memoryof the continuous-use defibrillator can store a first subset of one ormore self-tests while a second subset of one or more self-tests can bewirelessly downloaded into the continuous-use defibrillator on or aboutthe time it is desired to execute said second subset of one or moreself-tests. An advantage of storing zero or less than the fullcomplement of self-tests to be run on the continuous-use defibrillatoris a reduced requirement for memory storage to permanently store saidself-tests in the memory of the continuous-use defibrillator. Anotheradvantage is that downloaded self-tests can be tailored to account fornatural or age related variances in the components, subsystems, orsystems of the continuous-use defibrillator.

In an example, the results of one or more self-tests can be wirelesslycommunicated from the continuous-use defibrillator to a remote server orother remote storage device for storage in connection with thecontinuous-use defibrillator. This remote server or storage device canalso store or have access to other tests performed on the continuous-usedefibrillator or other self-tests run by the continuous-usedefibrillator. By examining tests run on the continuous-usedefibrillator or self-tests run by the continuous-use defibrillator,trends regarding the operational status or tolerances of components,subsystems, or systems of the continuous-use defibrillator can beanalyzed for actual or impending failures, whereupon appropriateremedial action to address the failure or impending failure can betaken, such as, without limitation, dispatching a replacement component,subsystem, or system of the continuous-use defibrillator for replacementby the user, sending out a replacement continuous-use defibrillator, orissuing a recall alert to the continuous-use defibrillator.

It is envisioned that also or alternatively to the wirelesscommunication capabilities of the continuous-use defibrillator, thecontinuous-use defibrillator can also comprise wired communicationcapabilities, such as, without limitation, plain old telephone service(POTS), a hard wired internet connection, a serial or parallel port, andthe like for communication with a remote device. In this example, thecontinuous-use defibrillator includes any suitable and/or desirablecommunication circuitry and interfaces, such as plugs and/orreceptacles, to facilitate such wired communication.

Assembly/Dis-assembly Sensing

In another example, the continuous-use defibrillator can comprise aharness, or a garment, such as a vest or shirt, that supports thecomponents, subsystems, or systems of the continuous-use defibrillatoron a patient during use. Prior to outfitting the patient with thedefibrillator, certain assembly may be needed. For example, in acontinuous-use defibrillator, an electrode belt may need to be assembledwithin the harness or garment. For example, the electrode belt mayinclude components such as a distribution node, therapy electrodes,and/or sensing electrodes that may be inserted within pockets in agarment. In such examples, the harness or garment can comprise sensorscoupled to portions of the harness or garment that are proximate to orcome in contact with the belt and/or components of the belt, and whichinform a microprocessor of the continuous-use defibrillator when thebelt and/or components of the belt are brought in contact with theharness or garment for assembly. In response to sensing an assembly (ordisassembly) event via such sensors, e.g., insertion or removal of atherapy electrode from a pocket in the garment, the microprocessor caninitiate one or more self-tests of the continuous-use defibrillator. Infurther examples, the device may sense the establishment of an operativeconnection between the electrode assembly (e.g., assembly 3) and themonitor (e.g., monitor 5) of the device. Such a connection may triggerone or more self-tests as described herein.

In an example, the harness or garment can comprise one or more snaps,buckles, or fasteners that facilitate securing the harness or garment onthe patient (or securing components, systems, and/or subsystems of thedevice within the garment) during use and removing the continuous-usedefibrillator from the patient. Each snap, buckle, or fastener cancomprise a sensor, the state of which can be detected by themicroprocessor, and which informs the microprocessor when the snap,buckle, or fastener is in a closed state or an open state. In responseto sensing the snap, buckle, or fastener is in a closed or open state(or has transitioned to the closed or open state), the microprocessorcan initiate one or more self-tests of the continuous-use defibrillator.

In one example, the snap, buckle, or fastener is a two-piece snap,buckle, or fastener wherein a first piece of the snap, buckle, orfastener has a mating arrangement that affirmatively mates with acorresponding mating arrangement of the second piece of the snap,buckle, or fastener. The first and second pieces can comprise first andsecond conductive segments (comprising the snap, buckle, or fastenersensor) that make contact when the two pieces are coupled together in aclosed state, e.g., when the continuous-use defibrillator is being wornby a patient, which conductive segments are separated when the snap,buckle, or fastener is in an open state, e.g., when the patient istaking off or not wearing the continuous-use defibrillator. In anexample, the first conductive segment can be coupled to a low voltage(e.g., 3 volt) source while the second conductive segment can be coupledin parallel to an input of the microprocessor and to ground potentialvia a current limiting resistor. In use, when the snap, buckle, orfastener is in the open state with the two segments not coupled, theinput of the microprocessor coupled to the second conductive segment isbiased to ground potential (analogous to a logical zero) via the currentlimiting resistor. In contrast, when the two segments are coupledtogether, the input of the microprocessor will detect the voltage of thelow voltage source (analogous to a logical one). Based on whether theinput of the microprocessor is sensing a logical zero or a logical one,the microprocessor can determine if the snap, buckle or fastener is inan open state, or a closed state, or when transitioning between an openstate and closed state, and vice versa, and can initiate self-testingupon any one or combination of these events. Other detection mechanismscan include capacitive elements, inductive elements, and/or elementsthat are capable of detecting changes in resistance and/or impedancevalues.

Round Robin Testing

In another example, the microprocessor of the continuous-usedefibrillator can be programmed to perform a different subset of thetotal number of self-tests of components, subsystems, or systems of thecontinuous-use defibrillator capable of being run each time a self-testcycle is initiated in some manner. For example, assume themicroprocessor is programmed to run the following self-tests: (1) one ormore I/O tests; (2) battery voltage test; (3) capacitor voltage test;(4) a high voltage converter output test; (5) battery power consumptiontest; (6) battery gas gauge test; e.g., draining faster/slower than itshows; and (7) a component test, e.g., the internal resistance of thebattery.

In a first test cycle, the microprocessor can run one or more ofself-tests 1-3; in a second test cycle the microprocessor can run one ormore of self-tests, e.g., 4-5; and, in a third test cycle themicroprocessor can run one or more of self-tests, e.g., 6-7.Alternatively, in the second test cycle, the microprocessor can run oneor more of self-tests, e.g., 3-5, and in the third test cycle themicroprocessor can run one or more of self-tests, e.g., 5-7 (i.e., anycombination of one or more tests in any test cycle can be the same ordifferent than any combination of one or more tests run in another testcycle).

Serialized Mismatch

In another example, various components, subsystems, or systems of thecontinuous-use defibrillator can be serialized in a manner that can beread by the microprocessor for comparison with serial numbers stored ina memory accessible to the microprocessor of the continuous-usedefibrillator. For example, unique serial numbers may be assigned to abattery, a wireless device, etc. of the continuous-use defibrillator andthese serial numbers can be stored in a memory, e.g., in the form of adatabase, accessible to the microprocessor of the continuous-usedefibrillator, e.g., during a set-up of the continuous-usedefibrillator. For example, unique serial numbers may be implementedthrough the use of radio-frequency identification (RFID) tags on thecomponents. An example of the use of identification devices in acontinuous-use defibrillator is disclosed in U.S. patent applicationSer. No. 14/448,761, which is hereby incorporated by reference in itsentirety. Thereafter, at one or more suitable times, the microprocessorcan read the serial number of each component and compare it to theserial number for that component stored in the memory. In the event aread serial number does not match a serial number for the correspondingcomponent, subsystem, or system stored in the memory, such as when acomponent, subsystem, or system has been replaced by a like componenthaving a different serial number, the microprocessor can initiateself-testing. This self-testing may comprise testing of all of thecomponents, subsystems, or systems of the continuous-use defibrillatortestable by the microprocessor or a subset of these components,subsystems, or systems including the component or subsystem that themicroprocessor detected as having the new serial number not stored inthe memory of the continuous-use defibrillator accessible by themicroprocessor.

For example, the microprocessor, upon detecting that a component orsubsystem has a new serial number not stored in the memory accessible tothe microprocessor, can initiate a self-test of the new component orsubsystem and, upon successfully passing the self-test, themicroprocessor can store the new serial number in the memory inreplacement of the serial number for the component or subsystem that wasreplaced. If the self-test of the new component or subsystem fails,however, the microprocessor can cause a suitable indication of thisfailure to be output, e.g., via LEDs or a visual display of thecontinuous-use defibrillator, or by signaling the occurrence of thefailure via wireless communication capabilities of the continuous-usedefibrillator.

Current Sensing

In another example, the continuous-use defibrillator can comprise acurrent sensor having an output that can be read and processed by themicroprocessor either directly, via an internal analog-to-digitalconverter (A-to-D) of the microprocessor, or indirectly, e.g., via adiscreet A-to-D disposed in the signal path between the output of thecurrent sensor and one or more inputs of the microprocessor andoperating under the control of the microprocessor. More specifically,the microprocessor can cause the output of the current sensor to besampled and can compare the sampled output to a pre-programmed valuestored in a memory accessible to the microprocessor indicative ofacceptable maximum (or minimum) current flow. In the event that thesampled output of the current sensor exceeds the stored pre-programmedvalue, suggestive of excessive (or too low) current flow, themicroprocessor can initiate self-testing of one or more of thecomponents, subsystems, or systems of the continuous-use defibrillator.In an example, the current sensor (e.g., an in-line resistor orhall-effect sensor) can be utilized by the microprocessor to monitor thecurrent output by the batteries of the continuous-use defibrillator.Should the microprocessor determine via the current sensor that thebatteries are supplying electrical current in excess (or less than) ofan electrical current value stored in the memory accessible via themicroprocessor, the microprocessor can initiate self-testing of one ormore components, subsystems, or systems of the continuous-usedefibrillator.

Temperature Sensor

In another example, the continuous-use defibrillator can comprise atemperature sensor coupled to the microprocessor, either directly or viasuitable A-to-D interface circuitry. The microprocessor can sample theoutput of this temperature sensor to detect the ambient temperature inwhich the continuous-use defibrillator is operating and can compare thisambient temperature to an upper temperature value stored in a memoryaccessible to the microprocessor indicative of a maximum desiredtemperature to which the continuous-use defibrillator is designed to beexposed. In response to detecting an ambient temperature greater thanthe preprogrammed maximum, the microprocessor can initiate self-tests ofcomponents, subsystems, or systems of the continuous-use defibrillator.In some implementations, the memory can be programmed with a temperaturevalue indicative of the lowest desirable temperature to which thecontinuous-use defibrillator is to be exposed and the microprocessor caninitiate self-testing of components, subsystems, or systems of thecontinuous-use defibrillator if, via the temperature sensor, themicroprocessor determines that the ambient temperature is below thislower temperature value stored in the memory. In an example, themicroprocessor can also be programmed to sense for a temperature changeoutside of predetermined limits or exposure to a rate of temperaturechange outside of predetermined limits.

Moisture Sensor

In another example, the continuous-use defibrillator can comprise amoisture sensor that is coupled directly or via suitable interfacecircuitry to the microprocessor. For example, the continuous-usedefibrillator can be rated according to an industry standard code, suchas, the International Protecting Rating (IP rating). A moisture sensorcan detect conditions and or events that are implicated, for example, bythe IP rating of the device. For instance, the moisture sensor can beconfigured to detect vertically dripping water and either provide analert or take corrective action (e.g., events that implicate an IP22rating). In some cases, the sensor can be configured to detect andrespond to water falling as a spray at a range of angles (e.g., up to60°) from the vertical, splashing from any direction against anenclosure of the device, projections from a nozzle against theenclosure, water ingress, and/or immersion.

In an example, the moisture sensor can comprise a pair of conductorsheld in spaced relation by or on a substrate. In the absence of moistureor water bridging the gap between the spaced conductors, no electricalcurrent will flow between the conductors in response a voltage appliedbetween the pair of spaced conductors. In contrast, in response tomoisture bridging the gap between the spaced conductors, an electricalcurrent will flow between the spaced conductors. The microprocessor canbe programmed to initiate self-testing in response to detectingelectrical current flow across the spaced conductors.

In some implementations, the microprocessor can be programmed to notinitiate self-testing based on the absence of current flow across thespaced conductors indicative of the absence of water or moisturebridging the spaced conductors. In order to detect current flow acrossthe spaced conductors, the moisture sensor can be coupled between aninput of the microprocessor and a suitable low voltage source. Thisinput can be one that the microprocessor periodically or aperiodicallysamples or can be an interrupt input of the microprocessor which, inresponse to detecting current flow across the spaced conductors,triggers an interrupt handling routine of the microprocessor thatinitiates self-testing of components, subsystems, or systems of thecontinuous-use defibrillator to determine if the exposure to moisture ishaving any effect on the operation of one or more of said components,subsystems, or systems of the defibrillator.

Remaining Battery Power

In another example, the microprocessor can be programmed to initiateself-testing based upon the remaining electrical power stored in thebattery of the continuous-use defibrillator. For example, upon detectingvia an A-to-D, that the available power is at, for example, withoutlimitation, 90% of the maximum available power in the battery, themicroprocessor can initiate self-testing of components, subsystems, orsystems of the continuous-use defibrillator. It is envisioned that oneor more other percentages of the power available in the battery may beutilized as a basis for initiating such self-tests.

Critical Error Handling

In another example, in response to the microprocessor receivingnotification of a potentially critical error of a component, subsystem,or system of the continuous-use defibrillator, the microprocessor can beprogrammed to disable and/or initiate a self-test of the component,subsystem, or system experiencing the potentially critical failure. Insome implementations, the microprocessor can cause a suitable warning togenerate an alert to the patient and/or the service center of thepotentially critical failure. The patient alert can be a tone output bya speaker, one or more lamps or LEDs of the continuous-use defibrillatorflashing, and/or the display of a warning message on a display of thecontinuous-use defibrillator. The warning to the service center may bevia a wired or wireless connection described above. For example, inresponse to the microprocessor determining a failure of a self-test of acomponent, subsystem, or system of the continuous-use defibrillator, themicroprocessor can be programmed to take appropriate remedial measures.In another example, in response to detecting a capacitor voltage inputfailure (e.g., of a capacitor of capacitor bank 67), the microprocessorcan be programmed to learn the charge time of the capacitor and thencharge the capacitor via time measurement instead of reading capacitorvoltage directly.

Upon the service center being notified of a failure of a component,subsystem, or system of the continuous-use defibrillator, or the entirecontinuous-use defibrillator, either via the microprocessorautomatically notifying the service center via a wired or wirelessconnection, or via the user notifying the service center, the servicecenter can record the occurrence of this failure and automaticallyinitiate a process of sending the patient a replacement component,subsystem, system or continuous-use defibrillator, as the case may be.For example, if a self-test determines that a battery is out oftolerance, the service center being informed of this fact, canautomatically initiate sending the patient a replacement battery.

Battery Replacement

Some of the self-tests described herein can be launched (manually orautomatically) when a battery is removed, replaced, or otherwiseejected. For example, the battery chamber may comprise a sensor thatdetects when a battery is either removed or inserted into the device andcause the device to initiate a selected series of self-tests. In someexamples, the sensor may indicate when a battery may have fallen out orotherwise ejected from the battery chamber. For example, in acontinuous-use defibrillator, a patient or a caregiver can replace thedefibrillator's batteries every day. In such cases, certain criticalself-tests can be performed immediately after the batteries arereplaced. For example, battery related tests for checking an outputvoltage and current threshold of the battery can be performedimmediately and whenever a battery is inserted into the battery chamber.In some examples, certain self-tests described herein can be launchedwhen a battery is replaced, but may be configured to be executed atdifferent intervals, e.g., every 2^(nd) or 3^(rd) time a batteryremoval/insertion event is detected. In some examples, if a criticalself-test fails, then additional self-tests described herein may beinitiated. In some examples, a patient may manually cause the device toperform one or more additional self-tests after insertion of thebattery.

As noted above, some of the tests described herein can be performeddaily, weekly, monthly, upon initialization of the continuous-usedefibrillator, e.g., after installing new patient parameters in a memoryaccessible to the microprocessor, in response to detecting an event,such as the buckle sensor transitioning from an open state to a closedstate or vice versa, the moisture sensor detecting moisture, themicroprocessor detecting a new serial number of a component, subsystem,or system of the continuous-use defibrillator, the microprocessordetecting via the accelerometer an impact in excess of a predeterminedimpact level, the receipt of a wired or wireless test signal from anexternal source, the detection, via a current sensor, of a current inexcess of (or less than) a preprogrammed current, a temperature greaterthan or less than a preprogrammed maximum or minimum temperature, thevalue of the gas gauge, and the like.

Where a continuous-use medical device, e.g., a continuous-usedefibrillator, includes multiple microprocessors, the detection of oneor more events and the launching of one or more self-tests can be underthe control of one or more of the microprocessors. In another example, acontinuous-use medical device can be configured whereupon a firstmicroprocessor has primary responsibility for detecting one or moreevents and launching of one or more self-tests, while a secondmicroprocessor can be configured to detect the one or more events andlaunch the one or more self-tests in the event the first microprocessordoes not timely launch the one or more self-tests in response to theoccurrence of the one or more events, e.g., the first microprocessor isnot detecting the one or more events or is not responding to the one ormore events. In another example, a first microprocessor and a secondmicroprocessor of the continuous-use medical device can be configured toperform a first subset and a second, different subset, respectively, ofthe available self-tests that can be performed.

Countdown Timer

In an example, the continuous-use defibrillator can include a countdowntimer (CDT) (not necessarily the WDT mentioned above) having an outputthat can be sensed by the microprocessor and which can, optionally, bereset via the microprocessor. The duration of the countdown period ofthe CDT can be selected in any suitable and/or desirable manner by oneskilled in the art. The countdown period can be on the order of seconds,minutes, days, weeks, months, or years. The microprocessor can beconfigured to be responsive to the expiration of the countdown periodfor initiating one or more self-tests. Optionally, the microprocessorcan be operative for resetting the countdown period to a starting valueafter expiration of a previous countdown period. In another example,also or alternatively to the CDT, the continuous-use defibrillator caninclude a time/date clock that the microprocessor can sample atdifferent times, compare a difference between two times/dates to apredetermined value stored in the memory, and can initiate one or moreself-tests when the difference exceeds the predetermined value.

Multi-tasking

In an example, the microprocessor can multi-task, with part of themicroprocessor's processing time dedicated to patient monitoring and/ortreatment and with another part of the microprocessor's processing timededicated to performing one or more self-tests. In this example, it isenvisioned that the processing time dedicated to patient monitoring doesnot compromise the microprocessor's monitoring and/or treatment of thepatient.

User Activity

In an example, the microprocessor can determine patient activity, e.g.,via an activity sensor, such as an accelerometer, and can decide basedon said determined activity whether or not to perform one or moreself-tests. In one example, in response to the microprocessordetermining that the patient is active and moving about, indicative ofthe absence of a life-threating cardiac event, the microprocessor canperform one or more self-tests. In another example, in response to themicroprocessor determining that the patient is stationary and that thepatient's ECG signals are normal, the microprocessor can perform one ormore self-tests. Further, one or more user actions may be the basis of aself-test initiated by the device. For example, a patient may manuallyselect one or more self-tests as described herein to cause the device toinitiate the selected self-test. For instance, if the patient wishes totest the charge holding capacity, charging circuitry, and/or convertercircuitry in connection with a readiness test, the patient may initiatea corresponding self-test of the relevant portion(s) and/or component(s)of the medical device. For instance, the patient may use the userinterface to browse to a screen displaying a list of diagnostic devicetests that the patient may select, e.g., by touching a touch-sensitivedisplay, a soft or physical button, providing a voice command, or otherinput. For example, the patient may be authorized to cause only a subsetof available self-tests to be executed on the device. In someimplementations, the patient may be remotely authorized via a remotewireless signal from a remote server to access one or more self-tests.In such cases, a remote technician may enable access to one or moreself-tests via the remote server. The patient may then interact with themedical device to cause the test(s) to execute and review the results.The results of such tests may also be transmitted to the remote serverand displayed to the remote technician via a workstation operativelycoupled to the remote server.

Post Shock Delivery

In an example, the microprocessor can initiate one or more self-testsafter administering one or more shocks to the patient.

Upload or Download of Data

In an example, the microprocessor can initiate one or more self-tests inresponse to the uploading of data into a memory or an RFID tag(discussed hereinafter) of the continuously on medical device or thedownloading data from the memory or the RFID tag of the continuously onmedical device, e.g., without limitation, via communication module 49 ordirectly into or out from the RFID tag. The data can include softwareand/or firmware. The data can also or alternatively include parameters,constants, and/or variables used in connection with software and/orfirmware. In an example, the microprocessor can set a flag in memorywhen uploading or downloading data. As a suitable time, in response tothis flag being set, the microprocessor can initiate one or moreself-tests.

Excessive Strain Detection

In an example, the continuous-use defibrillator can include one or morestrain gauges operatively coupled to the microprocessor for enabling themicroprocessor to detect when one or more components, subsystems, orsystems of the continuous-use defibrillator has experienced strain inexcess of a predetermined level of strain. For example, withoutlimitation, the PCB supporting one or more of controller module 47,communication module 49, energy storage module 44, and/or dischargemodule 42 can include thereon a strain gauge that is operatively coupledto enable the microprocessor to detect the output of the strain gauge.

In some examples, cabling used to connect one or more components (e.g.,in an electrode belt assembly, one or more cables are used to connectthe various therapy electrodes, and/or sensing electrodes, and/ordistribution node) can be subject to one or more tensile forces duringuse. For example, the cabling may be qualified according to tensilestrength tests specified in, for example, IEC 60601-2-4:2010, Clause201.15.4.101b Test1, and IEC 60601-1:2005, Clause 8.11.3.5. For example,the cabling may be required to sustain up to 25 cable pulls at a pullforce of 25 lbs. and have cable jacket displacement of less than 2 mm.Further, the cable tensile pull to failure requirement can be about 50lbs. minimum tensile strength. In some cases, the minimum tensilestrength can be set to withstand at least 75 lbs. Accordingly, sensorscan be placed, e.g., near or proximate to cable anchor point(s) (e.g.,tie-off points or strain clamps), or along the cable to detect cableand/or anchor point(s) forces in excess of one or more predeterminedtensile strength values. For example, if the tensile force comes within25% of a minimum tensile force, the monitor 5 can issue an alert to thepatient. Further, the monitor can immediately initiate a series ofself-tests to verify the integrity of the components of the device inaccordance with the principles described herein.

In an example, the strain gauge can be a piezoelectric transducer thatis coupled to the microprocessor via a D-to-A or a simpler circuit, suchas an electronic latch that compares the output of the strain gauge to apreset voltage level and switches the level and output between a logical0, a logical 1, or vice versa, in response to the voltage output by thestrain gauge exceeding the reference voltage, for example. In responseto the microprocessor detecting that the strain gauge has output avoltage indicative of detecting strain in excess of a predeterminedlevel of strain, the microprocessor can initiate one or more self-tests.

Tampering

In an example, a self-testing circuit (e.g., coupled to amicroprocessor) can initiate one or more self-tests in response todetecting tampering or attempted tampering of one or more components,subsystems, or systems of the continuous-use defibrillator. For example,to effect tampering detection, housing 31 of monitor 5 can include atleast two housing sections joined to form the housing 31 (e.g., atwo-piece housing), and further include a tampering detection element asthe monitoring component. For example, such a tampering detectionelement can include a breakaway conductor 74 (shown in phantom in FIG.2) that extends between the two housing sections. In some examples, thetampering detection element can include circuitry that is responsive tothe breakaway conductor 74 becoming an open circuit (i.e., the breakawayconductor breaks open) or becoming detached from one or both housingsections. Based on detecting the open circuit, the tampering detectionelement can trigger one or more self-tests to be performed by theself-testing circuit. In an example, the self-testing circuit can beimplemented by a microprocessor.

Accordingly, the tampering detection element can include the breakawayconductor 74 such that one end of breakaway conductor 74 can be coupledin parallel with an input of the microprocessor and a referencepotential (e.g., ground) via a biasing resistor. The other end ofbreakaway conductor 74 can be coupled to a voltage source. With the twohousing sections joined to form housing 31, the input of themicroprocessor detects the voltage of the voltage source impressedacross the biasing resistor via breakaway conductor 74 (analogous to alogical 1). When the two housing sections are opened, whereuponbreakaway conductor 74 becomes open or becomes detached from one or bothhousing sections, the voltage source becomes isolated from the input ofthe microprocessor and the input of the microprocessor is biased to thereference potential (analogous to a logical 0) via the biasing resistor.In response to detecting the change from the logical 1 to the logical 0,the microprocessor initiates one or more self-tests.

For example, self-tests can include performing one or moremicroprocessor self-tests, battery capacity tests, battery status,remaining run time, RAM/ROM tests, among others, and writing one or morestates and/or results of these tests to a nonvolatile memory for laterretrieval. For example, the monitor 5 can also display a warning messageto the user in connection with the tampering and/or attempted tampering.In some examples, the capacitor charge capacity can be checked throughone or more capacitor tests described below, and if a significant chargeis retained by the capacitor, a warning alarm sequence can be initiatedto warn the user of the potential for an electric shock.

Another example tampering detection that can cause a controller (e.g.,programmable logic devices and arrays, application specific integratedcircuits, hardware and software combinations, general purpose processorsand dedicated controllers) to display a notification that components ofa treatment device have been tampered with or damaged is disclosed inU.S. Pat. No. 8,649,861, which is incorporated herein by reference.

For example, the treatment device (e.g., the wearable defibrillator 1)can include one or more activity sensors, such as accelerometers. Forexample, a first accelerometer can be located on or within distributionnode 11 and a second accelerometer can be located on monitor 5. In oneembodiment, the first accelerometer is positioned on the subject's upperbody, and the second accelerometer is positioned proximate to thesubject's waist. Accelerometers or other activity sensors may also bepositioned on the subject's limbs. Activity sensors, includingaccelerometers, may include at least one position, force, or motiondetector. In one embodiment, a monitoring element can use informationdetected by multiple activity sensors, such as the accelerometers todetermine and predict subject activity, and to calibrate or verify theaccuracy of one or more sensors (e.g., electrode sensors and/or acousticsensors). For example, one or more of electrode or acoustic sensorstasked with determining the subject's heart beat may shift due tomovement or be improperly positioned so that an inaccurate (e.g.,reduced) heartbeat is reported. In this example, activity sensors mayindicate that the subject is exercising and where an elevated heartbeatwould be expected, while the sensors detect a reduced heart beat or noheart beat because it is improperly positioned on the subject. Acontroller can identify this discrepancy and notify the subject, forexample by a display on monitor 5, that one of the sensors should berepositioned. Further, based on this discrepancy identified as atriggering event, the self-test circuit can initiate a series ofself-tests, e.g., to verify the integrity of the sensing elements. Byprocessing sensed information and information received from the user,the self-test circuit may determine that one or more components,subsystems, or systems of the continuous-use defibrillator may have beentampered with or damaged, and the monitor 5 can display a notificationof any such tampering or damage.

Any one or combination of the above or following self-tests can be runin response to the insertion or removal of the battery, on a monthlyschedule, on a weekly schedule, on a daily schedule, or continually.

SELF-TESTS PERFORMED BY THE MEDICAL DEVICE Example Self-Test(s)

Examples of self-tests that can be run by self-testing components (e.g.,circuitry or microprocessors) comprise, without limitation, one or moreof the following tests: battery capacity; remaining battery run time;battery status; status of user response buttons; determining if ECGmonitoring signal quality is compromised by noise or electrode fall-off;ECG signal intensity, confirming detection algorithm parameters, therapyelectrode placement and impedance levels; and operation of variouselectrical components, subsystems, or systems of the continuous-usedefibrillator, for example, a DC-DC converter of the defibrillator. Morespecifically, self-tests that can be performed by the microprocessor cancomprise, without limitation, background checks of inputs and outputs(I/O); tests of the battery voltage, capacitor voltage, and a highvoltage converter; system-wide tests, such as testing battery powerconsumption, battery gas gauge draining faster/slower than it shows, oneor more individual component checks, like internal resistance of thebattery, and the like. Finally, tests can comprise looking at values ofindividual parts. Any combination of one or more self-tests can beinitiated by the microprocessor periodically, aperiodically, randomly,in response to receiving an appropriate signal at an input of themicroprocessor, in response to the microprocessor sampling at an input(analog and/or digital input) a condition of a component, subsystem, orsystem that the microprocessor is programmed to trigger a self-test inresponse to, or some combination thereof. Unless otherwise specified,the particular manner in which the self-testing component initiates oneor more self-tests is not to be construed as limiting the disclosure.

Microprocessor Self-Test

The microprocessor self-test is a functional test wherein the one ormore microprocessors within the medical device can test the integrity ofits internal registers and verify its access to local and externalmemory. Upon detecting a failure, the microprocessor can attempt tonotify the user of the system failure.

Gate Array

A system gate array self-test enables the microprocessor to verify thatit can write to and read from system gate array registers. This test canincidentally test other components, subsystems, or systems of thecontinuous-use defibrillator.

System Monitor

System monitor 5 self-test verifies that the microprocessor can write toand read from the system monitor.

CRC Test

A cyclical redundancy check (CRC) self-test is run on read only memory(ROM) of the continuous-use defibrillator to determine the functionalityof said ROM.

RAM Tests

A RAM or checksum self-test writes a pattern to system RAM and thencalculates a checksum based on the system RAM contents. This checksumtest can verify address and/or data faults within the RAM. A video RAMchecksum self-test can be similarly utilized to verify whether video RAMis experiencing address and/or data faults. A device/RAM checksum testcan determine if a flash RAM is experiencing an address and/or datafault.

Watchdog Timer (WDT)

A system watchdog verify self-test can verify if a watchdog timerdetectable by a microprocessor is working properly. For example, wherethe watchdog timer is coupled to an interrupt input of a microprocessor,the microprocessor can temporarily disable its interrupt input connectedto the output of the watchdog timer and then issues a reset command tothe watchdog timer. Thereafter, the microprocessor can monitor the timebetween when it outputs the watchdog reset signal and the time thedisabled interrupt input of the microprocessor changes state indicativeof the expiration of the watchdog timer. Based on this test, themicroprocessor can confirm that the watchdog timer is indeed functioningand outputting an appropriate expire signal within an appropriate timeinterval. In the event the watchdog timer either does not output theexpire signal or outputs the expire signal after a predetermined timeinterval programmed into the memory of the microprocessor, themicroprocessor can signal this as a failure of the watchdog timer.

Removable Memory Card

If the continuous-use defibrillator is provided with a removable memorycard, a card self-test can be provided to check for the presence andtype of removable memory card, and, optionally, a CRC or a RAM testmentioned above.

Electrode

For example, self-tests as described herein can be initiated when one ormore sensing and/or therapy electrodes are deemed as not makingsufficient contact with the patient. For example, an electrode may falloff the patient, or be disengaged from the patient during a patientactivity. Such electrode events may be based on, for example,determining a patient impedance as seen by the electrode. For instance,if the patient impedance exceeds a predetermined value, the device mayset a flag indicating electrode fall-off. Further, ECG self-tests canconfirm that the patient electrodes of the continuous-use defibrillatorwhen in use are properly receiving ECG signals from the patient and thatan ECG electrode has not fallen off. For example, a noisy ECG signal oran ECG signal that is prone to excessive variations may be a basis fordeclaring an ECG fall off event and setting a corresponding flag. Insome implementations, to determine whether an ECG electrode has fallenoff, a low amplitude 800 Hz signal is presented to a first ECG electrodethat is physically touching the patient's body. By sampling for this 800Hz signal at a second ECG electrode that is physically touching thepatient's body, the microprocessor can determine that the first andsecond ECG electrodes are indeed in contact with the patient's body. Theprocess of using one electrode to apply the low amplitude 800 Hz signaland a second electrode to detect the presence of the 800 Hz signal canbe repeated for each possible pair of electrodes provided for ECGmonitoring. In an implementation, the monitoring component asimplemented by a processor (e.g., processor 69) or circuitry 75 canexecute a state machine for carrying out ECG electrode fall off tests.In this regard, the monitoring component can effect a change in acorresponding flag in memory on detecting the ECG fall off event.

In an implementation, the monitoring component as implemented by aprocessor (e.g., processor 69) or circuitry 75 can execute a statemachine for carrying out therapy electrode fall off tests. For example,the processor or circuitry can detect an underlying parameter (e.g.,voltage drop indicative of a resistance of a path from the therapyelectrode to the patient's skin) that falls outside a predeterminedrange. If the voltage being measured is outside the predetermined range,then a therapy electrode fall off state is indicated. In response, themonitoring component can effect a change in a corresponding flag inmemory on detecting the therapy electrode fall off event.

Battery

Battery self-tests can also be run. For example, certain self-testsdescribed herein (including the battery self-tests) may be initiatedupon detecting when a battery charge level transgresses a predeterminedbattery charge threshold (e.g., 10% of full battery charge capacity).Different tests may be initiated at different battery charge levels. Forinstance, when the battery charge is at or below a critical charge level(e.g., 10%) the device may initiate a first set of self-tests that aredifferent when the battery charge level falls below anotherpredetermined threshold (e.g., 25%). One battery test can be theremaining battery power test mentioned above whereupon themicroprocessor can initiate self-testing upon detecting that theavailable power or voltage is at some predetermined percentage of themaximum available power or voltage in the battery. Another battery testcan be a battery load test where a no-load voltage of the battery(V_(NL)) is measured and, separately, the output of the battery isconnected to a load resistor and the voltage of the battery connected toa load (VL) and the current (IL) output by the battery to the loadresistor are measured. The internal battery resistance (R,) is thendetermined from the formula: R_(i)=(V_(NL)−V_(L))/I_(L), or anequivalent formula. If the microprocessor determines that the internalbattery resistance current falls outside of an acceptable limit, thiscan be deemed by the microprocessor to be indicative of battery failureor an impending battery failure.

Battery Charging

Another test is a test of the ability of the charger to charge thebattery. This test can involve the microprocessor monitoring the batteryvoltage during charging of the battery between a first voltage orpercentage of full charge and a second voltage or percentage of fullcharge and comparing this time to an acceptable time or range of timesfor charging the battery between these two voltages or percentages. Ifthe actual time to charge the battery is outside of the acceptable timeor range, the microprocessor can signal this as a potential problem withthe charger or the battery. One or more separate battery tests can beperformed to determine whether the battery is operating properly,whereupon if the battery is determined to be operating properly, themicroprocessor can be programmed to output an indication that thebattery charging circuitry is not operating properly.

Power Converter Test

The continuous-use defibrillator can comprise a high voltage powerconverter operating under the control of the microprocessor for chargingcapacitor bank 67 which stores the energy utilized to deliver a shock tothe patient at an appropriate time. In an example, capacitor bank 67comprises four parallel connected 650 μf capacitors each of which has a390 volt surge rating and which are charged by the high voltage powerconverter in approximately 20 to 25 seconds from a fully chargedbattery. Electrical current through the four parallel connectedcapacitors is limited by a charge resistor in series with a switchconnected to the parallel connected capacitors. When it is desired tocharge the capacitors, control signals from the microprocessor turn onthe high voltage power converter and close the switch in series with thecharge resistor. Under the control of the microprocessor, an A-to-D canmeasure and compare the output voltage of the high voltage powerconverter during charging of the capacitor bank to a predeterminedvoltage or range to verify operational integrity. For example, if theoutput voltage is substantially the same as the predetermined voltage orsubstantially falls within the predetermine voltage range, the powerconverter may be deemed to be operating as expected. For example, theresults of the power converter test may be written to one or moreregisters in the memory of the continuous-use defibrillator, e.g., forlater review by technicians. If the output voltage is not substantiallythe same as the predetermined voltage or substantially falls outside thepredetermined range, one or more flags may be set in the memory of thecontinuous-use defibrillator for review. If desired, the currentsupplied by the high voltage converter during charging of the capacitorbank can also be measured and compared via a current sensor connected toa different A-to-D or the same A-to-D that was utilized to measure thevoltage output by the high voltage converter, e.g., via a multiplexeralso under the control of the microprocessor. The current output by thehigh voltage power converter during charging of the capacitor bank canbe completed to a predetermined current value or predetermined currentrange similar to the voltage measurements described above.

Capacitor Charge Retention Test

A particular self-test can comprise measuring the ability of thecapacitor bank 67 to maintain a charge over a period of time. Forexample, the microprocessor, via an A-to-D, can measure the voltage ofthe capacitor bank 67 initially after charging and thereafter, on aperiodic or random basis, can measure the voltage of the capacitor bank67. Based on the change in voltage from the initially charged voltageover time, the microprocessor can determine if the capacitor bank isable to maintain a predetermined level of charge over a predeterminedperiod of time. Also, if the microprocessor determines that the chargein the capacitor bank 67 has dropped to an unacceptable level, themicroprocessor can cause the capacitor bank to be charged from the highvoltage power converter in the manner discussed above.

Capacitor Charge/Discharge Test

Also or alternatively, the capacitor bank of parallel connectedcapacitors can comprise in parallel therewith a discharge resistor and aswitch that operates under the control of the microprocessor. Herein, a“switch” can be a mechanical switch or a suitable semiconductortransistor. The discharge resistor can be utilized to safely dischargethe capacitor bank without having to actually shock a patient. In anexample, under the control of the microprocessor, the capacitor bank canbe alternately charged and discharged via the charging resistor and thedischarge resistor and the voltage and current during said charging anddischarging can be measured to determine whether the capacitor bank isoperating to predetermined criteria, e.g., charging to full capacitywithin a certain interval of time or range of time, discharging from astarting voltage level to a predetermined lower voltage level within apredetermined period of time or range of times, and the like.

In some implementations, the capacitor banks can be periodically charged(e.g., through the converter) and discharged (e.g., through a bank ofdischarge resistors as described below) to verify an integrity of thebattery and capacitor charge circuitry. (e.g., once or twice every weekaccording to a preset frequency and/or time parameter stored in memory)

Patient Discharge Resistor

In an example, the continuous-use defibrillator can be equipped withanother test load resistor to simulate the resistance of a patientconnected between of the capacitor bank, with the capacitors connectedin series instead of parallel for charging purposes. By way of this testload resistor, a self-test of the discharge capabilities of thecapacitor bank to a simulated patient can be performed. In the casewhere the continuous-use defibrillator applies a biphasic waveform to apatient, four transistors (IGBTs) arranged in an H-bridge configurationcan be utilized to deliver the two phases to the resistor acting in thecapacity as a simulated patient. By way of this test, the microprocessorcan determine if the transistors of the H-bridge are properly operatingby monitoring the voltage and/or current during discharge of thecapacitor bank through the test load resistance in both directions. Thetest load resistance (utilized to simulate a patient) can be connectedin parallel with the patient when the continuous-use defibrillator is inuse. A switch can be used to alternately connect the test loadresistance and the patient to the output of the capacitor bank duringtesting and in normal use. During testing, the switch connects the testload resistor to the output of the capacitor bank via the H-bridgeconfiguration and, by controlling the transistors on each leg of theH-bridge configuration, discharges the capacitor bank through the testload resistor. For the purpose of testing the switching capabilities ofthe transistors of the H-bridge configuration, the test load resistordoes not necessarily have to have the same resistance as a simulatedpatient. Rather, the test load resistor can have any resistance deemedsuitable and/or desirable for testing the switching capabilities of thetransistors of the H-bridge configuration. For example, whereas atypical patient may have a resistance of 50 ohms, the test load resistorcan have a resistance of, for example, without limitation, 200 ohms orgreater. Based on the discharge time of the capacitor bank determined ina manner known in the art based on the product of the capacitor valueand the test load resistor the microprocessor can calculate the value ofthe test load resistor and the capacitance of the capacitor bank. If thevalue of either the test load resistor or the capacitance of thecapacitor bank varies by more than a predetermined amount, this can beindicated as a failed self-test.

Shock Discharge

In another example, if the current being supplied to a patient duringdelivery of a shock falls below a normal level, this condition isindicative of one of the electrodes having become detached from thepatient.

Integrity Check of Cell or Bladder of One or More Therapy Electrode Pads

Each therapy electrode pad includes one or more conductive gelreservoirs, a.k.a., cells or bladders, each of which has a gel deliveryoutlet, wherein the gel reservoir is fluidly coupled to a fluid pressuresource. The fluid pressure source can be a source of any suitable and/ordesirable fluid pressure, such as, without limitation, an air pump, apressurized gas cylinder, and the like. A fluid channel can connect thefluid pressure source to each conductive gel reservoir. A suitablepressure gauge, such as a piezoelectric transducer or a gas pressurecontrolled switch can be coupled to measure the pressure in the fluidchannel and to provide an output that can be sampled by themicroprocessor, either directly or via a D-to-A. In use, under thecontrol of the microprocessor, fluid from the fluid pressure source canbe selectively introduced into the conductive gel reservoir to apressure level less than needed to open the gel delivery outlet of thegel reservoir. Thereafter, via the fluid pressure gauge, themicroprocessor can verify that the pressure applied to the conductivegel reservoir is maintained at or above a predetermined pressure for apredetermined interval of time.

For example, assume that the gel delivery outlet is configured to passconductive gel when the pressure applied to the conductive gel reservoiris greater than or equal to 10 psig. For the purpose of testing thefluid integrity thereof, the conductive gel reservoir can be exposed toa fluid pressure of, for example, 7 psig. Thereafter, the microprocessorcan monitor the time it takes for the pressure to fall from 7 psig to,for example, 5 psig (due to natural leakage of pressure from theconductive gel reservoir) and can compare this time to a time that isindicative of acceptable fluid integrity of the conductive gel reservoir(and the fluid conduit) to maintain a suitable level of fluid pressure.Details regarding therapy electrodes including conductive gel reservoirscan be found in U.S. Pat. Nos. 8,880,196 and 5,078,134, the contents ofboth of which are incorporated herein by reference.

Electrode/Therapy Pad Placement Sensing

In an example, the placement of one or more electrodes 7 a, 7 b, 7 c,and 7 d and/or one or more therapy pads 13 a, 13 b, 13 c at appropriatelocations of garment 2 can be sensed by the microprocessor. In responseto detecting proper or improper placement of one or more electrodes ortherapy pads, the microprocessor can output a suitable audio and/orvisual indication on monitor 5.

For example, without limitation, each electrode 7 a, 7 b, 7 c, and 7 dcan be positioned at a suitable location on garment 2 via a suitablefastener that includes two or more pieces that can be separated andjoined to form an open or closed electrical circuit that can be sensedby the microprocessor. In one example, one piece of the fastener can beconnected to a low-voltage, current-limited source of electrical powerwhile the other piece of the fastener can be connected in a manner fordetection by the microprocessor. For example, the other piece of thefastener can be connected in parallel to an input of the microprocessorand to an electrical ground via a current limiting resistor. In thisexample, when the two pieces of the fastener are not connected,whereupon the circuit formed by the fastener is open, the input of themicroprocessor will be at ground level via the current limiting resistor(analogous to a logical 0). In contrast, if the two pieces of thefastener are in a closed or connected state, whereupon the circuitformed by the fastener is closed, voltage from the low voltage sourcecan be impressed on the current limiting resistor via the closedfastener and the microprocessor can detect this voltage on the currentlimiting resistor (which voltage is analogous to a logical 1).

In an example, each therapy pads 13 a, 13 b, 13 c can be received in apocket of garment 2 wherein said pocket holds said therapy pad 13 a, 13b, 13 c in a desired position and in suitable pressure contact with apatient when the garment 2 is worn by the patient. Each pocket caninclude a fastener having a first part connected to a low voltage sourceand having a second, mating part, connected in parallel to groundpotential via a current limiting resistor and to an input of themicroprocessor, either directly or via interface circuitry. In a mannersimilar to the fastener discussed above in connection with electrodes 7a, 7 b, 7 c, and 7 d, when the fastener associated with therapy pads 13a, 13 b, 13 c is in an open state, the microprocessor senses thereference ground (analogous to a logical 0). In contrast, when thefastener is associated with the therapy pad is closed, the voltage fromthe low voltage source is impressed across the current limiting resistorand the microprocessor senses this voltage across the current limitingresistor (analogous to a logical 1).

While the use of fasteners on garment 2 has been described, it is alsoenvisioned that other means can be used for detecting the appropriatepositions of one or more electrodes and/or one or more therapy padswithin garment 2 when worn by a patient. For example, a side of anelectrode 7 a, 7 b, 7 c, and 7 d or therapy pad 13 a, 13 b, 13 c incontact with the harness, shirt, or other apparel forming garment 2 caninclude a conductive surface that, when appropriately positioned,creates an electrical continuity between a pair of spaced conductors ofthe harness, shirt, or other apparel. This continuity (or lack thereof)can be sensed by the microprocessor in any suitable and/or desirablemanner selected by one of ordinary skill in the art. In response todetecting continuity, the microprocessor interprets this as meaning thatthe electrode 7 a, 7 b, 7 c, and 7 d or therapy pad 13 a, 13 b, 13 c isappropriately positioned. In contrast, in the absence of suchcontinuity, the microprocessor can interpret this as the electrode ortherapy pad being out of position.

In response to determining that an electrode or therapy pad is or is notproperly positioned in garment 2 and in suitable contact with thepatient, the microprocessor can output a suitable audio and/or visualindication of this via monitor 5.

User Interface Test

In an example, in response to the microprocessor causing monitor 5 tooutput one or more predetermined visual images on display screen 43,and/or causing one or more predetermined audio tones output by a speakerport, and/or causing one or more predetermined lamps or LEDS of monitor5 to illuminate, the user can be prompted via an audio or visual promptto press one or more of the buttons of monitor 5 if the predeterminedimage is displayed on display screen 43, if the predetermined audiooutput is output by the speaker port, and/or if the one or morepredetermined lamps and/or LEDS are on thereby enabling the user toconfirm to the microprocessor the operational status of the displayscreen, the speaker port, and/or the lamps or LEDs.

In an example, the microprocessor can cause a predetermined image to bedisplayed on display screen 43 and can request a patient via the speakerto confirm that the predetermined image is, in-fact, being displayed bypressing a first button or by confirming that the predetermined image isnot being displayed by pressing a second button. In another example, themicroprocessor can cause the speaker port to output one or more messagesrequesting the user to press one or more buttons of monitor 5. Thebuttons can be mechanical buttons and/or virtual buttons displayed ondisplay screen 43.

In another example, microprocessor can request the user to press one ormore buttons in response to the operation of tactile simulator 12. Therequest to the user to press the one or more buttons can be made via avisual display on display screen 43 and/or via one or more messagesoutput by a speaker port.

Communications Capabilities

In an example, one or more self-tests can include periodic, aperiodic,or on-demand tests (e.g., based on a triggering event) of the devicecommunication capabilities, e.g., via the communications module. In someexamples, such tests can include establishing a link to a base stationand sending a wireless test signal. Both receiving and transmittingcapabilities can be tested through such a process. If the signals arereceived on one or both ends, appropriate flags can be written to thememory indicating the status of the communications capability. A similarprocess can be implemented for testing communications with a remoteserver.

Finally, it is envisioned that one or any combination of the foregoingconditions that trigger self-tests, any one or combination ofself-tests, and any one of more combination of the output of theself-tests can be implemented by the microprocessor of thecontinuous-use defibrillator.

OUTPUT OF SELF-TEST RESULTS

The results of one or more of the self-tests discussed hereinabove canbe displayed on a display of the continuous-use defibrillator and/orcommunicated to another device, such as a central processor or to asecond device, such as a smart phone, or tablet computer, which may beused as a diagnostic tool. Such displayed output may comprise theresults of one or more individual self-tests or a global indication,e.g., “self-tests pass” or “self-tests fail” and may compriseinstructions, such as “Notify the Manufacturer.” If the continuous-usedefibrillator comprises wireless communication capabilities, the resultsof self-tests can be wirelessly communicated to a service center forstorage and/or analysis. This wireless communication can also comprisethe identity and/or serial number of the continuous-use defibrillator,and/or a geographical location of the continuous-use defibrillatordetermined in any suitable or desirable manner, such as, withoutlimitation, via a GPS chip of the continuous-use defibrillator, ageographical location determined via a Wi-Fi address that thecontinuous-use defibrillator utilizes to communicate the test results tothe service center, and the like.

In another example, the continuous-use defibrillator can comprise anRFID tag that can be read by and/or written to by the microprocessor. Inthis example, test results can be stored in the RFID tag which can beread by a separate RFID reader, e.g., when the continuous-usedefibrillator is returned for service and/or refurbishment.

In another example, the continuous-use defibrillator can be configuredso that the microprocessor can be coupled into wired and/or wirelesscommunication with a remote user interface which can be operative fordisplaying individual self-test results and/or a global indication ofthe status of the external defibrillator, e.g., “self-tests pass” or“self-tests fail”.

Example Self-Test Flow

With reference to the generic flow diagram shown in FIG. 7, uponinitialization, the microprocessor, under the control of a controlprogram, advances to from a start step 130 to a step 132 where themicroprocessor senses for one or more conditions that trigger one ormore self-tests. This sensing by the microprocessor can be on a periodicor aperiodic sampling basis of one or more inputs of the microprocessoror can be initiated by the microprocessor in response to a signal at oneor more interruptible inputs of the microprocessor that are configuredto respond to the signal by interrupting normal program execution andexecuting one or more interrupt service routines associated with saidone or more inputs. The use of interruptible inputs and interruptservice routines to terminate normal program execution in amicroprocessor is well known in the art and will not be discussedfurther herein for the purpose of simplicity.

In response to the microprocessor not sensing one or more triggerconditions, program flow loops on step 132. However, in response to themicroprocessor sensing one or more trigger conditions, program flowadvances from step 132 to step 134 wherein the microprocessor executesone or more self-tests in response to the sensed trigger conditions.Upon completion of the one or more self-tests, program flow advances tostep 136 where the microprocessor outputs self-test results, e.g., ondisplay screen 43. Program flow then returns to step 132.

A non-exhaustive list of example events that can trigger one or moreself-tests in step 132 is shown in FIG. 8. A non-exhaustive list ofexample self-tests that the microprocessor can execute in step 134 inresponse to sensing a trigger condition is shown in FIG. 9.

Example Self-Test Process—Battery Replacement

With reference to FIG. 10, an example flow diagram of a self-test thatcan be run by the microprocessor in response to a depleted first batterybeing replaced with a second battery will now be described. Afterinitialization, microprocessor advances from start step 140 to step 142wherein the microprocessor senses for substitution of a depleted firstbattery with a second battery having a greater terminal voltage orcharge than the first battery. This sensing by the microprocessor canoccur via an A-to-D that is operative for sensing the terminal voltageof the first or second battery operatively coupled to the continuouslyon medical device, such as, without limitation, a continuous-usedefibrillator.

If, in step 144, the microprocessor senses that the first battery hasbeen replaced with the second battery having a greater terminal voltageor charge than the first battery, the microprocessor advances to step146. In contrast, if, in step 144, the microprocessor does not sense thefirst battery has been replaced with the second battery having a greaterterminal voltage or charge than the first battery, the microprocessorloops on steps 142 and 144 until sensing that the first battery has beenreplaced with the second battery having a greater terminal voltage orcharge than the first battery.

Upon advancing to step 146, the microprocessor executes/runs one or moreof the battery related self-tests from the list of example self-testsshown in FIG. 9. Upon completion of the one or more battery relatedself-tests in step 146, the microprocessor advances to step 148 wherethe microprocessor outputs the results of the one or more batteryrelated self-tests, e.g., on display screen 43. Thereafter, program flowreturns to step 142 where the microprocessor once again loops on steps142-144 until sensing the substitution of a depleted first battery witha second battery having a greater terminal voltage or charge than thefirst battery.

Uses of Triggering Events and Example Self-Tests

In an example, the continuous-use medical device can be an ambulatorymedical device, such as the wearable defibrillator 1 described above.However, this is not to be construed as limiting the invention since itis envisioned that a continuous-use medical device does not necessarilyhave to be an ambulatory medical device.

In an example, the continuous-use medical device, e.g., an ambulatorymedical device, includes a sensing component to be disposed on a patientfor detecting a physiological signal, e.g., a cardiac signal, of thepatient. In an example, this sensing component can be one of theelectrodes 7 a-7 d discussed above. Circuitry can be provided thatcomprises a monitoring component for monitoring for a triggering eventand a self-test component for executing one or more self-test procedureson the ambulatory medical device. In one example, the monitoringcomponent and self-test components can be controlled by circuitry 75 asdescribed above and/or one or both processors 69, 71. For example, themonitoring component can include any suitable hardware and/or softwaremodule or element that can monitor for any one or combination of theexample triggering events shown in FIG. 8, for example, and discussedabove. Examples of monitoring components include an accelerometer, apiezoelectric device, or any other suitable and/or desirable devicecapable of detecting impact, especially impact above a certain level; atemperature sensor for sensing a temperature greater than or less than apredetermined maximum or minimum temperature; a moisture sensor fordetecting moisture in excess of a predetermined moisture level; a strainsensor for detecting strain on a component, subsystem, or system of themedical device in excess of a predetermined strain level.

The monitoring component can also or alternatively include one or moreelements for processing signals indicative of a triggering event. In anexample, these elements can include a microprocessor, a programmablelogic device (PLD), a programmable gate array (PGA), anapplication-specific integrated circuit (ASIC), analog and/or digitalchips, one or more active components, such as transistors, passivecomponents, or any combination of the foregoing.

The self-test component can include any one or combination of elementsthat are capable of performing operations associated with the one ormore self-test procedures, including a microprocessor, computer memoryor storage, a PLD, a PGA, an ASIC, analog and/or digital chips, activecomponents, passive components, or any combination of the foregoing.Moreover, the monitoring component and the self-test component can bethe same element or can include elements in common.

In an example, the monitoring component is always operational formonitoring during a period beginning from when the physiological signalof a patient is first sensed by the sensing component and ending whenthe monitoring is no longer needed for the patient. The medical devicecan also include a therapeutic element for delivering electrotherapy toa patient and can comprise a garment worn about a torso of the patient.When the continuous medical device comprises a garment worn about atorso of the patient, the period beginning when the physiological signalof the patient is first sensed can be when the garment is initiallydonned by the patient.

Examples of when the physiological signal of the patient can be firstsensed include, without limitation, when the sensing component is in anoperative position to commence acquiring the physiological signal of thepatient, when the physiological signal is received from the sensingcomponent by a processing component that is configured to process thephysiological signal, when the physiological signal is processed by theprocessing component for the purpose treatment analysis, and/or when thephysiological signal is stored in a memory.

Examples of when monitoring is no longer needed for the patient caninclude, without limitation, the patient being implanted with sensingand monitoring components; a changed physical condition of the patientwhereupon the patient is medically required to use a different medicaldevice; the patient being switched to a different device having more orfewer functions; the patient being switched to a different device usedby a different caregiver; and/or the patient being moved from oneenvironment to another (e.g., from department store to ambulance, fromambulance to hospital, from ambulance to helicopter, etc.).

In some implementations, the monitoring component can be operational formonitoring during at least one of the following events: changing of apower source of the ambulatory medical device; removal of and donning ofthe sensing component by patient for patient showering or bathing;replacement of a garment that comprises the ambulatory medical deviceworn about a torso of the patient; and replacement of a patient signalsensor. Replacement of the patient signal sensor can be in response towear of the patient signal sensor over a time due to use.

In another example, the continuous medical device, such as, withoutlimitation, an ambulatory medical device, can include a sensingcomponent, such as one of the electrodes 7 a-7 d discussed above, to bedisposed on a patient for detecting a physiological signal of thepatient. The medical device can include circuitry configured to detect achange in a software or firmware configuration of the ambulatory medicaldevice. This circuitry can include a microprocessor that is coupled tomemory or storage that contains program code that is readable by themicroprocessor and which enables the microprocessor to determine when asoftware or firmware configuration stored in another part of the same ora different memory or storage has changed.

In an example, the memory can store information regarding each softwareand/or firmware module stored on the ambulatory medical device. Thisinformation can include, without limitation, a checksum, a versionnumber, and/or a revision number of each software and/or firmwaremodule. Thereafter, operating under the control of the program code, themicroprocessor can compare the checksum, version, and/or revision of oneor more software or firmware modules stored on the ambulatory medicaldevice with checksums, versions, and/or revisions stored in the memoryfor a match or mismatch. In the event of a mismatch, indicative of achange in a software or firmware configuration of the ambulatory medicaldevice, a self-test component of the ambulatory medical device canexecute one or more self-test procedures on the medical device, e.g.,one or more of the self-tests shown in FIG. 9, for example.

The self-test component can include the same or a differentmicroprocessor as was used to detect a change in the software orfirmware configuration of the ambulatory device, either alone or incombination with other components required to perform the one or more ofthe self-tests. In an example, the self-test component can perform asystem-wide test (test no. 11 in FIG. 9) that not only tests one or morecomponents but also tests, indirectly, the operational capabilities ofintermediate components, such as an analog-to-digital converter, gatearrays, multiplexors, and biasing elements.

In an example, the change in the software configuration can comprise asoftware or firmware update to software or firmware of the ambulatorymedical device. In another example, the change in the software orfirmware configuration can comprise an update to one or more deviceparameters set in the ambulatory medical device. An example of a deviceparameter includes a threshold level. Examples of threshold levelsinclude a maximum moisture threshold to be detected before triggering aself-test, a maximum threshold temperature, above which a self-test istriggered, or a minimum temperature to be sensed before triggering aself-test.

Another example continuous-use medical device, such as an ambulatorymedical device, includes a sensing component, such as, withoutlimitation, one of the electrodes, 7 a-7 d discussed above, to bedisposed on a patient for detecting a physiological signal of thepatient. Circuitry is provided comprising a monitoring component formonitoring a triggering event and a self-test component for executingone or more self-test procedures on the ambulatory medical device. Themonitoring component and the self-test component can be as describedabove.

In this example, the monitoring component is always operational formonitoring whether or not a primary source of power is available in theambulatory medical device.

In an example of such an ambulatory medical device, the circuitry caninclude first and second components that are coupled to the primarysource of power. A secondary source of power can be coupled to the firstcomponent, but not to the second component, for supplying electricalpower to the first component when the primary source of power is notsupplying electrical power to the first component, such as when theprimary source of power is either unable to supply electrical power oris unavailable to supply electrical power. Examples of when the primarysource of power is either unable to or unavailable to supply electricalpower, whereupon the secondary source of power supplies power to thefirst component, includes (1) when the primary source of power is areplaceable battery that is in the process of being replaced; and (2)when the primary source of power to the first and second components hasbeen terminated by an action by the patient, e.g., when the garment isremoved from the patient, or when power from the primary source of poweris terminated to the first and second components for some purpose, suchas the patient removing the garment, including the primary source ofpower, for showering or bathing, or the removal of one or more of theelectrode assembly, monitor 5, distribution note 11, electrodes 7 a-7 d,and/or therapy electrodes 13 a-13 c from one garment and installingthese elements in another garment.

In an example, the primary source of power can be a main battery that isused with the ambulatory medical device and the secondary source ofpower can be a secondary or backup battery, a capacitor, or asupercapacitor, such as a double layer capacitor or a lithium-ioncapacitor, an inductor, or any other energy storage device that cansupply electrical power only to a subset of the components of theambulatory medical device when the primary source of power isunavailable or not able to supply electrical power.

In an example, the secondary source of power supplies power to the firstcomponent, but not to the second component, when the primary source ofpower is unable to or unavailable to supply electrical power. In anexample, the first component can be the monitoring component formonitoring for a triggering event. In another example, the firstcomponent can be the combination of the monitoring component and theself-test component for executing one or more self-test procedures onthe ambulatory medical device.

In an example, in response to the monitoring component detecting anevent when the primary source of power is not able to or is notavailable to supply electrical power to the first component, the firstcomponent, operating with electrical power from the secondary source ofpower, can (a) cause a first subset of the one or more self-testprocedures to be performed on the ambulatory medical device or (b) delayperforming a second subset of the one or more self-test procedures untilthe primary source of power is supplying electrical power to the firstcomponent. In an example, this delay can be almost zero, such as whenthe primary source of power has been momentarily disconnected.

The first and second subsets of the one or more self-test procedures canbe the same or different.

In an example, a plurality of self-test procedures can be provided forexecution on the ambulatory medical device. Within a first period oftime following the primary source of power becoming not able to or notavailable to supply electrical power to the first component, theplurality of self-test procedures can be performed. Following this firstperiod of time, less than all of the plurality of self-test procedurescan be performed.

In an example, the secondary source of power and the first component canbe configured such that step (a) or step (b) above can be performed fora period of time when the primary source of power is not able to or isnot available to supply electrical power to the first component that isat least one week or at least one month.

In an example, the first component can be operative for directly orindirectly monitoring for the occurrence of the event. The firstcomponent can indirectly monitor for the occurrence of the event via acomponent, subsystem, or system of the ambulatory medical device that isconfigured to convert the event into form for processing by the firstcomponent. In an example, the first component can comprise one or moremicroprocessors, microcontrollers, or other integrated device such as,without limitation, one or more ASICs, PLDs, and/or FPGAs. In anexample, the first component is a low power consumption device that isconfigured in the continuous-use medical device to always be powered on,either from the primary source of power or the secondary source ofpower—in an example, when the primary source of power is not supplyingpower to the first component, to detect for one or more triggeringevents and to execute one or more self-tests (or cause one or moreself-tests to be executed) in response to detecting the one or moretriggering events.

Another example continuous-use medical device, such as an ambulatorymedical device, includes a sensing component, such as one of theelectrodes 7 a-7 d, to be disposed on a patient for detecting aphysiological signal of the patient. The ambulatory medical devicecomprises a monitoring component for monitoring for a triggering eventand a self-test component for executing one or more self-test procedureson the ambulatory medical device. The monitoring component and/or theself-test component can be the same as described above.

The monitoring component can be always operational (powered on) formonitoring during a monitoring period beginning from when the sensingcomponent is first configured to begin detection of the physiologicalsignal of the patient and ending when the sensing component isconfigured to no longer be capable of detecting the physiological signalof the patient. An example of when the sensing component is firstconfigured to begin the detection of the physiological signal of thepatient occurs when a component, subsystem, or system of the ambulatorymedical device is activated whereupon it becomes capable of receivingdata from the monitoring component indicative of the detectedphysiological signal of the patient. An example of when this sensingcomponent is configured to no longer be capable of detecting thephysiological signal of the patient occurs when power is removed fromsaid component subsystem or system of the ambulatory medical device.

The ambulatory medical device can further include a therapeutic elementfor delivering electrotherapy to the patient. The continuous-use medicaldevice can also include a garment worn about a torso of the patient.

In another example, a self-test circuit of the ambulatory medical devicestill receives power even when the primary source of power is notsupplying power to the ambulatory medical device, such as when theambulatory medical device is shut off for (1) replacement of the primarysource of power, e.g., a main battery of the ambulatory medical device,(2) the patient shuts down the ambulatory medical device for showeringor bathing, and/or (3) exchanging one garment of the ambulatory medicaldevice for another garment. In any of these instances, when the deviceis shut off, the self-test circuit is still capable of performing one ormore self-test procedures, such as, without limitation, detecting amoisture level via the moisture detector, detecting a temperature viathe temperature sensor, or any one or more of the self-tests disclosedin FIG. 9. In an example, the monitoring component and/or the self-testcircuit can be one or more low power consumption devices that areconfigured in to always be powered on for detecting for one or moretriggering events and/or for executing one or more self-tests (orcausing one or more self-tests to be executed) in response to detectingthe one or more triggering events, respectively.

Another example continuous-use medical device, such as an ambulatorymedical device, includes a monitoring component for monitoring for oneor more triggering events different from an intended medical use of orintended medical purpose for the medical device that could potentiallyprevent the medical device from functioning for its intended purpose;and a self-test component responsive to the one or more triggeringevents for executing one or more self-tests procedures on the ambulatorymedical device.

The one or more triggering events can include: excessive mechanicalshock; exposure to temperature greater than a predetermined maximumtemperature or less than a predetermined minimum temperature; exposureto excessive moisture; excessive strain on a component, subsystem, orsystem of the medical device; exposure to a temperature change outsideof predetermined limits; exposure to a rate of temperature changeoutside of predetermined limits; prolonged vibration outside a timelimit or an amplitude limit; passage of time beyond a predeterminedlimit; and/or a change in ambient pressure beyond a predetermined limit.

In an example, the continuous-use medical device can include a ambientpressure sensor that is operative for sensing ambient pressure andproviding an indication thereof to the monitoring component which can beconfigured to compare the indication of the sensed ambient pressure to apredetermined pressure value. Detection that the indication of thesensed ambient pressure is greater than (or less than) the predeterminedpressure value can be treated by monitoring component as a triggeringevent that the self-test component can be responsive to for executingone or more self-tests procedures on the ambulatory medical device.

The embodiments have been described with reference to various examples.Modifications and alterations will occur to others upon reading andunderstanding the foregoing examples. Accordingly, the foregoingexamples are not to be construed as limiting the disclosure.

What is claimed is:
 1. An ambulatory medical device, comprising: asensing component to be disposed on a patient for detecting aphysiological signal of the patient; and monitoring and self-testcircuitry configured for detecting a triggering event and initiating oneor more self-tests based on detection of the triggering event, whereinthe ambulatory medical device senses the physiological signal of thepatient substantially continuously over an extended period of time. 2.The ambulatory medical device of claim 1, wherein the triggering eventcomprises at least one of an impact and a vibration event experienced bythe ambulatory medical device.
 3. The ambulatory medical device of claim2, wherein the at least one of the impact and the vibration eventexperienced by the ambulatory medical device corresponds to one of animpact level that exceeds a predetermined impact level and a vibrationlevel that exceeds a predetermined vibration level.
 4. The ambulatorymedical device of claim 2, wherein at least one of the impact and thevibration event experienced by the ambulatory medical device correspondsto an impact duration that exceeds a predetermined impact duration and avibration duration that exceeds a predetermined vibration duration. 5.The ambulatory medical device of claim 2, further comprising anelectromechanical switch for detecting the at least one of the impactand the vibration event experienced by the ambulatory medical device. 6.The ambulatory medical device of claim 2, further comprising at leastone of a single axis accelerometer, a multi-axis accelerometer, and apiezoelectric transducer for detecting the at least one of the impactand the vibration event experienced by the ambulatory medical device. 7.The ambulatory medical device of claim 2, wherein the one or moreself-tests comprise tests of at least one of a device, component, andsubsystem of the ambulatory medical device to ensure that the at leastone of the impact and the vibration event has not adversely affected theat least one of the device, component, and subsystem.
 8. The ambulatorymedical device of claim 1, wherein the triggering event comprises atleast one of a software update, a device configuration update, and apatient parameter change.
 9. The ambulatory medical device of claim 8,wherein the at least one of the software update, the deviceconfiguration update, and the patient parameter change is initiatedremotely.
 10. The ambulatory medical device of claim 8, wherein thedevice configuration update comprises an update to one or more deviceparameters set in the ambulatory medical device.
 11. The ambulatorymedical device of claim 1, wherein the triggering event is based on auser action or activity.
 12. The ambulatory medical device of claim 1,wherein the triggering event is a wireless test signal.
 13. Theambulatory medical device of claim 12, wherein the wireless test signalis initiated at a remote support center.
 14. The ambulatory medicaldevice of claim 1, wherein the triggering event is based on a detectingof at least one of battery replacement, battery removal, and batteryejection.
 15. The ambulatory medical device of claim 1, wherein thetriggering event is based on a battery level transgressing apredetermined battery charge threshold.
 16. The ambulatory medicaldevice of claim 1, wherein the triggering event is based on a signalindicating that one or more electrodes is making insufficient contactwith the patient's skin.
 17. The ambulatory medical device of claim 1,wherein the triggering event is in response to detecting moisture inexcess of a predetermined moisture level.
 18. The ambulatory medicaldevice of claim 1, wherein the triggering event is in response todetecting strain on a device component in excess of a predeterminedstrain level.
 19. The ambulatory medical device of claim 1, wherein thetriggering event is in response to detecting a temperature of at leastone of the device or a component of the device greater than apredetermined maximum temperature or less than a predetermined minimumtemperature.
 20. The ambulatory medical device of claim 1, wherein thetriggering event is in response to detecting an operative connectionbetween one or more electrodes and the medical device.
 21. Theambulatory medical device of claim 1, wherein the triggering eventcomprises at least one of replacement of a garment that comprises theambulatory medical device worn about a torso of the patient, replacementof a patient signal sensor, and a prompt for replacement of at least oneof the garment and the patient signal sensor in response to wear of theat least one of the garment and the patient signal sensor over time dueto use.
 22. The ambulatory medical device of claim 1, wherein the one ormore self-tests comprises one or more tests related to a type of thetriggering event.
 23. The ambulatory medical device of claim 1, whereinthe triggering event is initiated by or within a device, component, orsubsystem of the ambulatory medical device, and the one or moreself-tests comprise one or more tests of the device, component, orsubsystem of the ambulatory medical device that initiated or caused thetriggering event.
 24. The ambulatory medical device of claim 1, whereinthe monitoring and self-test circuitry is configured to classify thetriggering event and, based on the classification, determine whether toinitiate a self-test of the continuous use medical device.
 25. Theambulatory medical device of claim 1, wherein the monitoring andself-test circuitry is configured to store a flag in a memory of theambulatory medical device indicating a status of the triggering event.26. The ambulatory medical device of claim 1, wherein the monitoring andself-test circuitry is always operational for the monitoring whether aprimary source of power is available in the ambulatory medical device.27. The ambulatory medical device of claim 26, wherein the primarysource of power is a main battery for use with the ambulatory medicaldevice.
 28. The ambulatory medical device of claim 26, wherein when theprimary source of power is not able to or is not available to supplyelectrical power, a secondary source of power provides power to themonitoring and self-test circuitry.
 29. The ambulatory medical device ofclaim 28, wherein the secondary source of power comprises at least oneof a backup battery, a capacitor, an inductor, and a supercapacitor. 30.The ambulatory medical device of claim 28, wherein, responsive to thetriggering event when the secondary source of power is providing powerto the monitoring and self-test circuitry at least one of: performing asubset of the one or more self-test with power from the secondary sourceof power, and delay performing the subset of the one or more self-testuntil the primary source of power is supplying electrical power to themonitoring and self-test circuitry.
 31. The ambulatory medical device ofclaim 28, wherein the monitoring and self-test circuitry, operating withpower from only the secondary source of power, is operational formonitoring during at least one of the following: replacement of theprimary source of power; at least one of removal of and donning of thesensing component by the patient for patient showering or bathing;replacement of a garment that comprises the ambulatory medical deviceworn about a torso of the patient; and replacement of a patient signalsensor.
 32. An ambulatory medical device comprising: a sensing componentto be disposed on a patient for detecting a physiological signal of thepatient; at least one of a component, subsystem and system disposedwithin the ambulatory medical device and operatively coupled to thesensing component; a memory configured to store one or more programscorresponding to one or more predetermined self-tests to be performed onthe at least one of the component, subsystem and system; and at leastone processor executing a self-test component configured to cause theexecution of the one or more programs stored in the memory to performthe one or more predetermined self-tests on the at least one of thecomponent, subsystem and system on a predetermined schedule; wherein theambulatory medical device is continuously operational during amonitoring period.
 33. The ambulatory medical device of claim 32,wherein the monitoring period begins from when the sensing component iscaused to begin the detection of the physiological signal of the patientand ends when the sensing component is caused to no longer detect thephysiological signal of the patient.
 34. The ambulatory medical deviceof claim 32 further comprising at least one therapeutic element forproviding a therapeutic shock to the patient.
 35. The ambulatory medicaldevice of claim 32, wherein the one or more predetermined self-testscomprise at least one of the following battery tests: a battery capacitytest, a battery internal resistance test, a battery status test, and abattery charger test.
 36. The ambulatory medical device of claim 32,wherein the one or more predetermined self-tests comprise a powerconverter test configured to test at least one of an output voltage anda current of a converter, a capacitor charge retention test, and acapacitor charge/discharge test.
 37. The ambulatory medical device ofclaim 32, wherein the one or more predetermined self-tests comprise atest of response buttons of the ambulatory medical device.
 38. Theambulatory medical device of claim 32, wherein the one or morepredetermined self-tests comprise a test of one or more processors ofthe ambulatory medical device.
 39. The ambulatory medical device ofclaim 32, wherein the one or more predetermined self-tests comprise atest of at least one of the sensing component and a therapeutic elementof the ambulatory medical device.
 40. The ambulatory medical device ofclaim 32, wherein the one or more predetermined self-tests comprise atest of at least one of a user interface of the ambulatory medicaldevice and a communications module of the ambulatory medical device. 41.The ambulatory medical device of claim 32, wherein the self-testcomponent is always operational for the one or more predeterminedself-tests whether or not a primary source of power is available in theambulatory medical device.
 42. The ambulatory medical device of claim41, wherein the primary source of power is a main battery for use withthe ambulatory medical device.
 43. The ambulatory medical device ofclaim 41, wherein when the primary source of power is not able to or isnot available to supply electrical power, a secondary source of powerprovides power to the at least one processor.
 44. The ambulatory medicaldevice of claim 43, wherein the secondary source of power comprises atleast one of a backup battery, a capacitor, an inductor, and asupercapacitor.
 45. The ambulatory medical device of claim 43, wherein,when the secondary source of power is providing power to the at leastone processor at least one of performing a subset of the one or morepredetermined self-tests with power from the secondary source of power,and delay performing the subset of the one or more predeterminedself-tests until the primary source of power is supplying electricalpower to the at least one processor.
 46. An ambulatory medical device,comprising: a sensing component to be disposed on a patient fordetecting a physiological signal of the patient; and circuitrycomprising a monitoring component for detecting a triggering event, anda self-test component for executing one or more self-test procedures onthe ambulatory medical device, wherein the ambulatory medical device isalways operational during a monitoring period.
 47. The ambulatorymedical device of claim 46, wherein the monitoring period begins fromwhen the sensing component is caused to begin the detection of thephysiological signal of the patient and end when the sensing componentis caused to no longer detect the physiological signal of the patient.48. The ambulatory medical device of claim 46, further comprising atherapeutic element for delivering electrotherapy to the patient. 49.The ambulatory medical device of claim 46, wherein the ambulatorymedical device comprises a garment worn about a torso of the patient.50. A continuous use medical device comprising: a sensing component fordetecting a physiological signal of a patient; a memory; and a processoroperatively connected to the sensing component and the memory, theprocessor configured to detect at least one of an impact and a vibrationevent experienced by the continuous use medical device; and in responseto detecting the at least one of the impact and the vibration eventexperienced by the continuous use medical device, store a flag in thememory of the continuous use medical device.
 51. The continuous usemedical device of claim 50, wherein the flag is configured to beretrieved from the memory when continuous use of the continuous usemedical device ends.
 52. The continuous use medical device of claim 50,wherein the flag, when retrieved from the memory, provides an indicationthat at least one of the impact and the vibration event occurred. 53.The continuous use medical device of claim 52, wherein the indication isdisplayed on at least one display device along with informationassociated with the indication to allow for review of the indication andthe information by service personnel.
 54. The continuous use medicaldevice of claim 50, wherein the at least one of the impact and thevibration event experienced by the continuous use medical devicecorresponds to one of an impact level that exceeds a predeterminedimpact level and a vibration level that exceeds a predeterminedvibration level.
 55. The continuous use medical device of claim 50,wherein at least one of the impact and the vibration event experiencedby the continuous use medical device corresponds to an impact durationthat exceeds a predetermined impact duration and a vibration durationthat exceeds a predetermined vibration duration.
 56. The continuous usemedical device of claim 50, further comprising an electromechanicalswitch for detecting the at least one of the impact and the vibrationevent experienced by the continuous use medical device.
 57. Thecontinuous use medical device of claim 50, further comprising at leastone of a single axis accelerometer, a multi-axis accelerometer, and apiezoelectric transducer for detecting the at least one of the impactand the vibration event experienced by the continuous use medicaldevice.
 58. The continuous use medical device of claim 50, wherein theprocessor is further configured to, in response to detecting the atleast one of the impact and the vibration event experienced by thecontinuous use medical device, initiate one or more self-tests of thecontinuous use medical device.
 59. The continuous use medical device ofclaim 58, wherein the one or more self-tests comprises tests of one ormore devices, components, and subsystems of the continuous use medicaldevice to ensure that the at least one of the impact and the vibrationevent has not adversely affected any or the one or more devices,components, and subsystems.